When you upgrade a Microsoft Application Virtualization (also known as App-V) client from Windows Vista to Windows 7, you receive the following error message:
Program Compatibility Report The program is blocked due to compatibility issues. Report the problem to see if a solution is available. Windows will automatically display a website with more information about compatibility problems. Microsoft Application Virtualization is incompatible with this version of Windows. For more information, contact Microsoft.
For the details of the issue and the resolution see the following Knowledge Base article:
KB976248 - Error message when you upgrade an Application Virtualization client from Windows Vista to Windows 7: "Program Compatibility Report"
J.C. Hornbeck | System Center Knowledge Engineer