VC Issue faced while developing an application

I am working on a standard Visual C MFC application. There is a file say x.abc, whenever I double click this file, it opens directly in my VC app. This VC app is running as administrator and that is the requirement of the project. Case
1: Now, in Windows 7, when User Access Control (UAC) is ON, and I double click on file with .abc extension, it gives error message "There was a Problem sending the command to program" and the file doesn't open and neither does that app. Case
2: If my VC exe is already open and then I double click .abc file, it gives error "There was a Problem sending the command to program" and then the file opens. This problem occurs in Windows 7 with UAC ON only. Let me know if you have experienced the similar problem.
By the way, I am using the methods EnableShellOpen(); RegisterShellFileTypes(FALSE);
