Error in SL 4

[yaip]

I upgraded my application from SL 3 to SL 4. Now when I deploy it here, I get:

Could not load file or assembly 'System.Windows, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' or one of its dependencies. The system cannot find the file specified.

I check if there are any references to old assemblies. There are none. Has anyone experienced this?

[cwpcentral]

yaip, silverlight 4 can not use any 2.0 framework assemblies. so if one of you controls or assemblies was compiled against the 2.0 framework then your toast. there is some information on the web about how to be able to call and use other assemblies but don't remember where i saw it. i only looked at 200 links to get my small appilcation up and running.