Garmin 765T Won't mount on imac

My garmin 765T won't mount on my powerpc imac. I am running system 10.4.11. The nuvi drive shows in the system info device box but will not show on the desk top on in disk utility. I have mounted it on a friend's mac and it worked fine--so the issue definitely seems to be my mac. I have reinstalled my system and that did not help. I've seen the problem discussed in a number of forums, but no solutions that anyone has said has worked...

any help, please...

you can create a test user and configure your device on it.

If it works the problem is in your user account... and you need to delete some garmin preferences in your user account

Regards