I went to the site you recommended, and managed to get it going.
A couple of things might help your sticky.
1. The technique works for Windows Mobile 5 and TomTom Navigator 6 (which is what I have) as well as TomTom Navigator 5.
2. The error is due to a corrupted Windows Mobile registry entry - why the hell doesn't Microsoft fix it?
3. To edit the registry, download the Resco Explorer from
http://www.resco.net/pocketpc/explorer/default.asp (Resco's URL at the other thread doesn't work...)
Thank you very much for your help.