Shoot. Can you email me your TopoFusion.ini file? It should be here:
C:\Documents and Settings\*Your USER NAME*\Local Settings\Application Data\TopoFusion\TopoFusion.ini
Slight possibility it is just in C:\Program Files\TopoFusion, since I know you have been a TF user for quite a while.
Thanks, I'll see if I can get to the bottom of it.