Hi,
Could be that different drive is an untested situation.
A simple test is maybe to use OpenMap and give the rith path with it including the drive. Like this (with exact your path of course):
Code:
MP.OpenMap('U:\Program Files\Microsoft MapPoint Europe\MP2004\Templates\New European Map.ptt', False);
If that helps, I suggest to search in registry for MP or MapPoint or .ptm and related things to see if drive letters are associated.