Deadlock

bonjour ,
j ai eu un message d'erreur :
La transaction (ID de processus 52) a été bloquée sur les ressources verrou par un autre processus et a été choisie comme victime. Réexécutez la transaction.
je pensais connaitre la procédure stockée où se produit ce problème, mais je ne sais pas comment le détecter , il y a 2 tables qui veulent faire la même action ou quelque chose du genre de deadlock .. je ne sais pas exactement de quoi s'agit de phénomène....
Voici la procédure :

USE [Pharmatica]
GO
/****** Object:  StoredProcedure [dbo].[FinDel]    Script Date: 07/09/2013 09:24:36 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[FinDel]
@iIdVente int,
@NewNumVenteErrorChek int=0
AS
declare @iIdArticle int,
@dPrix decimal(16,2),
@iStock int,
@iQteReserve int,
@iQteServie int,
@sDate varchar(50),
@iUnite int,
@iUniteGratuiteVente int,
@iIdTransVente int,
@iMois int,
@iAnnee int,
@iNbreVente int,
@iQteVendu int,
@iSomme int,
@iConsommation int,
@iVenteMois int,
@fPrixVente decimal(16,2),
@iMAJQteStock int,
@iStockTotal int,
@iMAJUniteGratuite int,
@iUniteGratuitePdt int,
@QteReserve int, @StockTotal int
begin transaction
	SET @sDate = convert(varchar(50),getdate(),103)
	declare encours cursor FOR 
		SELECT id_trans_vente,transactions_lingne_ventes.id_article,prix_unit_ttc_article,stock_article_stock,qte_reserve_article_stock,qte_servie_ligne,unite_gratuite_article_stock
		FROM transactions_lingne_ventes,article_stock
		WHERE id_vente=@iIdVente
		AND transactions_lingne_ventes.id_article=article_stock.id_article
		AND transactions_lingne_ventes.prix_unit_ttc_article=article_stock.prix_vente_article_stock
	OPEN Encours
		FETCH NEXT FROM Encours
		INTO @iIdTransVente,@iIdArticle,@dPrix,@iStock,@iQteReserve,@iQteServie,@iUnite
		WHILE @@FETCH_STATUS = 0
		BEGIN
		IF(@iQteServie>0)
		begin		
			IF(@iUnite>=@iQteServie)
			begin
				SET @iUniteGratuiteVente = @iQteServie
			end
			else
			begin
				SET @iUniteGratuiteVente = @iUnite
			end
			SET @iUnite = @iUnite - @iUniteGratuiteVente
			UPDATE transactions_lingne_ventes SET unite_gratuite_ligne=@iUniteGratuiteVente WHERE id_trans_vente=@iIdTransVente
			SET @NewNumVenteErrorChek = @@ERROR
			UPDATE article_stock SET unite_gratuite_article_stock = @iUnite WHERE id_article=@iIdArticle AND prix_vente_article_stock LIKE @dPrix
			SET @NewNumVenteErrorChek = @@ERROR
		end
		else
		begin
			IF(@iUnite>0)
			begin
				SET @iUniteGratuiteVente = @iQteServie
			end
			else
			begin
				SET @iUniteGratuiteVente = 0
			end
			--set @iUnite = @iUnite - @iUniteGratuiteVente
			UPDATE transactions_lingne_ventes SET unite_gratuite_ligne=@iUniteGratuiteVente WHERE id_trans_vente=@iIdTransVente
			SET @NewNumVenteErrorChek = @@ERROR
		end
 
 
 
 
 
------------------------------------------------------------------------------------------------------------------------------------------
		--------------------MAJ historique article et nbre vente article
		--exec MAJArticle @iIdArticle,@iQteServie,1,@sDate
 
	SET @iNbreVente = (SELECT DISTINCT NBR_SORTIE_ARTICLE FROM ARTICLE WHERE ID_ARTICLE=@iIdArticle)
	IF @iNbreVente= NULL
		begin
			SET @iNbreVente = 0
		end
	SET @iNbreVente = @iNbreVente	+ 1
 
	SET @iQteVendu = (SELECT DISTINCT NBR_VENTE_ARTICLE FROM ARTICLE WHERE ID_ARTICLE=@iIdArticle)
	IF @iQteVendu=NULL
		begin
			SET @iQteVendu = 0
		end
	SET @iQteVendu = @iQteVendu + @iQteServie
 
	UPDATE ARTICLE
	SET NBR_VENTE_ARTICLE = @iQteVendu,
	NBR_SORTIE_ARTICLE= @iNbreVente,
	DATE_DERN_SORTIE_ARTICLE=@sDate
	WHERE ID_ARTICLE=@iIdArticle
	SET @NewNumVenteErrorChek = @@ERROR
--
SET @iMois = month(getdate())
SET @iAnnee = year(getdate())
-----------
--test si le pdt existe ds la table historique pr le mois et l'annee courante
 SET @iSomme =(SELECT count(*) FROM HISTORIQUE_ARTICLE WHERE ID_ARTICLE=@iIdArticle AND annee_historique_article=@iAnnee AND mois_historique_article=@iMois)
 IF(@iSomme>0)
--si il existe on fait la MAJ
	begin
		UPDATE historique_article
		SET NBR_VENTE_MOIS_ARTICLE = (SELECT NBR_VENTE_MOIS_ARTICLE FROM HISTORIQUE_ARTICLE WHERE ID_ARTICLE=@iIdArticle AND annee_historique_article=@iAnnee AND mois_historique_article=@iMois) + @iQteServie,
		NBR_SORTIE_MOIS_ARTICLE=  (SELECT NBR_SORTIE_MOIS_ARTICLE FROM HISTORIQUE_ARTICLE WHERE ID_ARTICLE=@iIdArticle AND annee_historique_article=@iAnnee AND mois_historique_article=@iMois) + 1
		WHERE ID_ARTICLE=@iIdArticle AND annee_historique_article=@iAnnee AND mois_historique_article=@iMois
		SET @NewNumVenteErrorChek = @@ERROR
 
		---MAJ VENTE_MOIS_ARTICLE et CONS_MOIS_ARTICLE de la table article
		SET @iVenteMois = 0
		SET @iConsommation = 0
		SET @iVenteMois = (SELECT VENTE_MOIS_ARTICLE FROM article WHERE id_article=@iIdArticle)
		IF(@iVenteMois IS NULL)
 
		begin
			SET @iVenteMois = 0
		end
		SET @iConsommation = (SELECT CONS_MOIS_ARTICLE FROM article WHERE id_article=@iIdArticle)
 
		IF(@iConsommation IS NULL)
		begin
			SET @iConsommation = 0
		end
		SET @iConsommation = @iConsommation + @iQteServie
		SET @iVenteMois = @iVenteMois + 1
-------------------------------------------------------------------------
		UPDATE article SET CONS_MOIS_ARTICLE=@iConsommation,VENTE_MOIS_ARTICLE=@iVenteMois WHERE ID_ARTICLE=@iIdArticle
		SET @NewNumVenteErrorChek = @@ERROR
-------------------------------------------------------------------------
	end 
else
	begin
		INSERT INTO historique_article(id_article,annee_historique_article,mois_historique_article,NBR_VENTE_MOIS_ARTICLE,NBR_ACHAT_MOIS_ARTICLE,NBR_SORTIE_MOIS_ARTICLE,NBR_ENTREE_MOIS_ARTICLE) VALUES(@iIdArticle,@iAnnee,@iMois,@iQteServie,0,1,0)
		SET @NewNumVenteErrorChek = @@ERROR
-------------------------------------------------------------------------
UPDATE article SET CONS_MOIS_ARTICLE=@iQteServie,
		VENTE_MOIS_ARTICLE=1,
		NBR_SORTIE_ARTICLE=@iQteServie,
		NBR_VENTE_ARTICLE=1
		 WHERE ID_ARTICLE=@iIdArticle
 
		SET @NewNumVenteErrorChek = @@ERROR
-------------------------------------------------------------------------
	end
 
----------------
		SET @NewNumVenteErrorChek = @@ERROR
		SET @iStock		= @iStock - @iQteServie
		SET @iQteReserve	= @iQteReserve - @iQteServie
 
------------------------------------------------------------------------------------------------------------------------------------------
		---------------------MAJ Stock
		--exec MAJQteReserveArticle @iIdArticle,@iQteReserve,@dPrix,1,@iStock
SET @iMAJQteStock=1
SET @iStockTotal=0
SET @iMAJUniteGratuite=0
 
/*MAJ de la Qte Reserve ds ARTICLE_STOCK et ARTICLE*/
UPDATE 
	ARTICLE_STOCK
SET
	QTE_RESERVE_ARTICLE_STOCK= @iQteReserve
 
WHERE 
	ID_ARTICLE=@iIdArticle
	AND
	PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix
SET @NewNumVenteErrorChek = @@ERROR
 
UPDATE 
	ARTICLE
SET
	QTE_RESERVE_ARTICLE= (SELECT sum(QTE_RESERVE_ARTICLE_stock) FROM ARTICLE_stock WHERE ID_ARTICLE=@iIdArticle)
 
WHERE 
	ID_ARTICLE=@iIdArticle
SET @NewNumVenteErrorChek = @@ERROR	
 
/*MAJ STOCK ARTICLE STOCK*/
IF(@iMAJQteStock>0)
begin
	---insertion ds la table mouvement article
	declare @iStock1 int,
	@iQte int
		SET @iStock1 = (SELECT top 1 STOCK_ARTICLE_STOCK FROM ARTICLE_STOCK WHERE ID_ARTICLE=@iIdArticle AND PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix)
		SET @iQte     = @iStock - @iStock1
		IF(@iQte!=0)
		begin
			INSERT INTO mouvement_article(date_mouvement,stock_ancien,nature_mouvement,qte_modifie,prix_vente_article,id_article) VALUES(GETUTCDATE(),@iStock1,'VENTE',@iQte,@dPrix,@iIdArticle)
			SET @NewNumVenteErrorChek = @@ERROR
		end
 
	/*MAJ de stock  de l'article */
		UPDATE
			ARTICLE_STOCK
		SET
			STOCK_ARTICLE_STOCK=@iStock,
			date_vente_article_stock = convert(varchar(50),getdate(),103)
		WHERE
			ID_ARTICLE=@iIdArticle
			AND
			PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix
		SET @NewNumVenteErrorChek = @@ERROR
		IF(EXISTS(SELECT * FROM article_stock WHERE ID_ARTICLE=@iIdArticle AND PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix AND suppression LIKE 'oui'))
		begin
			IF(@iStock!=0)
			begin
				UPDATE 	ARTICLE_STOCK SET suppression='NON' WHERE ID_ARTICLE=@iIdArticle AND PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix
				SET @NewNumVenteErrorChek = @@ERROR
			end
		end
		UPDATE
			ARTICLE
		SET
			STOCK_TOTAL_ARTICLE=(SELECT sum(STOCK_ARTICLE_STOCK) FROM ARTICLE_STOCK WHERE ID_ARTICLE=@iIdArticle)
		WHERE
			ID_ARTICLE=@iIdArticle
		SET @NewNumVenteErrorChek = @@ERROR
		IF(@iMAJUniteGratuite!=0)
		begin
			SET @iUniteGratuitePdt = (SELECT unite_gratuite_article_stock FROM article_stock  WHERE ID_ARTICLE=@iIdArticle AND PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix)
			IF(@iUniteGratuitePdt IS NULL)
			begin
				SET @iUniteGratuitePdt = 0
			end
			SET @iUniteGratuitePdt = @iUniteGratuitePdt+@iUnite
			UPDATE article_stock SET unite_gratuite_article_stock=@iUniteGratuitePdt  WHERE ID_ARTICLE=@iIdArticle AND PRIX_VENTE_ARTICLE_STOCK LIKE @dPrix
			SET @NewNumVenteErrorChek = @@ERROR
		end
 
end
------------------------------------------------------------------------------------------------------------------------------------------
SET @NewNumVenteErrorChek = @@ERROR
-----------------------------------
FETCH NEXT FROM Encours 
INTO @iIdTransVente,@iIdArticle,@dPrix,@iStock,@iQteReserve,@iQteServie,@iUnite
END
CLOSE Encours
DEALLOCATE Encours
--commit transaction
IF @NewNumVenteErrorChek = 0 
	BEGIN
		COMMIT TRANSACTION
	END
else
	BEGIN
		ROLLBACK TRANSACTION
	END

si par hasard vous sauriez où est exactement se produit ce message d'erreur .
Merci