PublicKeyToken=b77a5c561934e089 ... is invalid problem

[Ing. Rajesh Kumar]

Hi everybody
I had a system with WinXP Pro; framework 1.1; MSDE; IIS 5.
I installed on it :
framework 2 beta; SqlServer 2005 beta and Visual Web Developer beta.
There was no error during the installation but when i load VWD and
drag and drop a server control on the WebForm it says :
GetConfig was called during configuration Initialization. I get the
same error even when i click on the search button in help in VWD. I
played around with the system and tried to do different things but
never got VWD to get work.

At the end i uninstalled everything from the system.
Now i have there only :
Framework 2 beta and VWD beta. No SqlServer or Framework 1.1 but i
still cannot run the *.aspx files.
It says :
The format of the file 'System.Data, Version=2.0.3600.0,
Culture=neutral, PublicKeyToken=b77a5c561934e089' is invalid OR
The format of the file 'System.Xml, Version=2.0.3600.0,
Culture=neutral, PublicKeyToken=b77a5c561934e089' is invalid.
how to fix this ? I am looking forward to play with the framework 2.

Thanks in advance
Raja