The .Net framework 4.0 is a Microsoft programming framework used by Sync & Save. This error indicates that it is installed on your computer, but your user does not have sufficient rights to use it.  Try running Sync & Save as Administrator: Right click on the icon on the start menu and choose properties.  Switch to the Compatibility tab and check off Run this program as an administrator.

See this post for possible sources of the problem: http://social.msdn.microsoft.com/Forums/pl-PL/windowscompatibility/thread/b121a1d2-6c5a-4c1b-b773-cb2bcc5aad64