using web.config for ASP.NET produces 500 Internal Server Error

[KienN]

I've just installed Plesk 9.2 into my Windows server 2008
One of my customer do upload his ASP.net work onto my Hosting, if he doesn't use the web config file, his website got no problems

But if he uploads his webconfig file onto his web, it appears to be seen Error 500 (Internal Server Error)


Does anyone have appropriate answer for me? I've been looking for answer in Google but no hopes.
Please answer me as soon as possible! Here or through my email [email protected]

Thanks so much!