Message html illisible

Bonsoir,

je reçois un message html depuis mon site.
il s'affiche correctement sous outlook 2003, thunderbird, netcourrier mais sous outlook express il prend la forme ci dessous :
avez-vous une idée ce ce qui se passe ?
peut-on relire correctement ce message ?

merci à tous

> X-Sender: xxx>
> Errors-To: xxx
> X-Mailer: PHP
> X-Priority: 3
> From:xxx
> MIME-Version: 1.0
> Content-Type: multipart/mixed;
> boundary="----=_001"
> Message-Id: <20091018181927.7D74E2FE4A@60gp.ovh.net>
> X-Ovh-Tracer-Id: 6632676353248866255
> X-Ovh-Remote: 213.186.35.30 (18.mail-out.ovh.net)
> X-Ovh-Local: 213.186.33.29 (mx1.ovh.net)
> X-Spam-Check: DONE|U 0.5/N
>
>
> This is a multi-part message in MIME format.
>
> ------=_001
> Content-Type: multipart/related;
> boundary="----=_002"
>
>
> ------=_002
> Content-Type: multipart/alternative;
> boundary="----=_003"
>
>
> ------=_003
> Content-Type: text/plain; charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
>
>
>
>
> ------=_003
> Content-Type: text/html; charset="iso-8859-1"
> Content-Transfer-Encoding: base64
>
> PGh0bWw+PG1ldGEgaHR0cC1lcXVpdj0nQ29udGVudC1UeXBlJyBjb250ZW50PSd0ZXh0L2h0bWw7
> IGNoYXJzZXQ9aXNvLTg4NTktMSc+PGJvZHk+PGNlbnRlcj48aW1nIHNyYz0naHR0cDovL3d3dy5h
> dWJlcmdlZGVsYXZlbmlyLmNvbS9pbWFnZXMvZW50ZXRlLmpwZycgYm9yZGVyPScwJz48L2NlbnRl
> cj48YnI+PGJyPjxiPkRlbWFuZGUgZGUgZGV2aXM8L2I+PGJyPjxociBzaXplPTIgYWxpZ249Y2Vu
> dGVyIGNvbG9yPScjMTI5ODA2Jz48dGFibGU+PHRyPjx0ZCB3aWR0aD01MCU+PGJyPk1lbGxlIC8g
> TW1lIC8gTS4gJm5ic3A7TUVURVlFUiAgJm5ic3A7belsYW5pZTxicj52b3VzIOp0ZXMgOiAgJm5i
> c3A7UGFydGljdWxpZXI8YnI+NCBydWUgZGUgbGEgY3JvaXg8YnI+PGJyPjxicj43NzE2NyZuYnNw
> O09STUVTU09OPGJyPjwvdGQ+PHRkPjxicj48YnI+PGJyPlTpbOlwaG9uZSBmaXhlIDogMDE2NDI5
> ODg1OTxicj5U6WzpcGhvbmUgUG9ydGFibGUgOiA8YnI+PGJyPkUtbWFpbCA6IG1lbGllMjAwOEBo
> b3RtYWlsLmZyPGJyPjwvdHI+PC90YWJsZT48aHIgc2l6ZT0yIGFsaWduPWNlbnRlciBjb2xvcj0n
> IzEyOTgwNic+PHRhYmxlPjx0cj48dGQ+PGI+RGF0ZSA6IDwvYj4yMGp1aW4gMjAxMDxicj48Yj5O
> b21icmUgZGUgcGVyc29ubmVzIDo8L2I+IDQwIOAgNTA8YnI+Qydlc3QgdW5lIHNvaXLpZSAmbmJz
> cDsgcG91ciA6IE1hcmlhZ2U8YnI+PGI+Q29tZW50YWlyZXMgOiA8L2I+PGJyPk5PVVMgQUlNRVJP
> TlMgREVDT1JFUiBMQSBTQUxMRSBTVFlMRSBUQUhJVEkgUEFSIE5PUyBTT0lOUy4uLi5wb3VyIGxh
> IGRhdGUgZXhhY3RlIHNpIHZvdXMgZXRlcyBub24gbGlicmUgb24gcGV1dCBtb2RpZmllciBsYSBk
> YXRlIC4uLm1lcmNpIGRlIG5vdXMgZmFpcmUgdW4gZGV2aXMgLi4ubWVyY2kgcG91ciB0b3V0PGJy
> PjwvdGQ+PC90cj48L3RhYmxlPjxociBzaXplPTIgd2lkdGg9JzEwMCUnIGFsaWduPWNlbnRlciBj
> b2xvcj0nIzEyOTgwNic+PC9odG1sPiA=
>
>
>
> ------=_003--
>
> ------=_002--
>
> ------=_001--