I have windows 2008 r2 installed on my server, so iis 7.5 is. I am not able run any of the class.net applications on iis. one of the compression modules throws exception. Detailed Error Information Module DynamicCompressionModule Notification SendResponse Handler StaticFile Error Code 0x8007007e Requested URL http://localhost:8081/a.html Physical Path C:\inetpub\TestWebSite\a.html Logon Method Anonymous Logon User Anonymous i tried diferent logon methods, different sites even static html pages are not served. Error never changes. sorry for poor english.