Error when Check Access

Jul 2, 2009 at 8:18 PM

I get the following error when I try to check any user's access:

Could not load file or assembly 'System.DirectoryServices.AccountManagement, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.

Dec 17, 2009 at 6:12 PM

I get the very same error message. Even after retracting/removing/re-deploying the solution. Any ideas?