I've had that strange error this mid-day... I am unable to understand why System.Data could depend on System.Data.SqlClient.

This occurs in Mono under Linux, and I don't depend on SQL Server whatsoever, incidentally...

Oh! It states it's merely a warning however the compiler stops doing the work job anyway.

Compilation Error

Description: Error producing a resource needed to service this request. Take a look at source file and modify it to repair this error.

Compiler Error Message: : ** (/usr/local/lib/mono/2./gmcs.exe:8658): WARNING **: The course System.Data.SqlClient.SortOrder could 't be loaded, utilized in System.Data, Version=2..., Culture=neutral, PublicKeyToken=b77a5c561934e089 ~/Global.asax

System.Data.SqlClient.SortOrder lives in System.Data.dll. I'm surprised Mono has not implemented this straightforward enum, but apparently it has not:

http://go-mono.com/status/status.aspx?reference=2.0&profile=2.0&assembly=System.Data

You (or some auto-produced code) should be referencing it, possibly in Global.asax.