New Post: Error while approving Update

Hello,

when i want to approve an Update in WPP, i get this error Message:

"Could not load file or assembly 'System.Web, Version=4.0.0.0,
Culture=neutral, PublicKeyToken='b03f5f7f11d50a3a' or one of its
dependencies. Das System kann die angegebene Datei nicht finden."

Of course i reinstalled .NET Framework, but it didn't help.
I tried to publish the Adobe Flash Player package from the documentation..

Does anyone know this error?

PS: It's the first time i use WPP..