Truecrypt et Windows 7

Bonjour,

Il m'est impossible de mettre en oeuvre Truecrypt, logiciel décrit comme étant compatible avec Windows 7.

Le message suivant s'affiche :

Truecrypt Volume Creation Wizard
Access was denied by the operating system,
Possible cause: The operating system requires that you have
read/write permission (or administrator privileges) for certain
folders, files, and devices, in order for you to be allowed to read
and write data to/from them. Normally, a user without
administrator privileges is allowed to create, read and modify
files in his or her Documents folder.

Merci pour votre aide.