[IIS7.5] Error I can't understant

Hi !

I've been working on a website with PHP5 in local (with WampServer) and everything worked great. I uploaded everything in a friend's server and took a domain name with 1&1.

The server is running Microsoft Server, and I have the 500.0 error (0x00000001) : 

HTTP Error 500.0 - Internal Server Error

The page cannot be displayed because an internal server error has occurred.

How do I fix this ? I have no idea how Ms Server works, and neither for IIS.

I use URL Rewriting, maybe that's it.

Sorry for my English, I'm French

Thanks

iSteelZ