I've talked to JRiver and they are at a loss. I seem to be the only one having the problem.
I suspect the problem has something to do with Windows Media Player because of two things:
1 - When I installed the latest MC build, it required a reboot. That never happens unless there is a Windows Media Player change.
2 - After the first instance of MC shutting down at G-Force start I reinstalled G-Force 3.54 and got an error message that G-Force_WMP.dll could not be installed because it was in use.
I renamed the file (I could rename but not delete) and didn't get the error message again but WMP was not active at the time. After subsequent uninstall - reinstall of Media Center, G-Force and Windows Media Player I have not gotten that message again but G-Force still aborts Media Center. It works with WMP but not MC.
Has anyone encountered this before or have ANY idea what it might be?
CVIII

Update: I posted this in the General Forums when I see that I should have posted it here. I see that I am NOT the only one with this problem.