Glad to hear you got MC working again. As I said in the email I sent you, i've had a look at the files you sent me, and i'm a bit stumped as to why MC is crashing. Menu Mender doesn't appear to have touched ehres.dll, and everything I can see in your registry looks ok.
The behaviour you describe with TVTonic (replacing another app on the menu) is actually Media Center default behaviour - the newest installed app always gets the spot on the menu. However, TVTonic does seem to come up a lot in Menu Mender support issues - maybe it is doing something odd.