I'm now using one of the conflictive PC's, it's really weird, I've been doing some testings with the proximitySenderDemo, and got the same results: Every mobile device is asked for a password.
As far I can know, the app started working well until they disconnected the dongle and connected again (or so they say) :S I don't know how to solve this, I've changed the dongle to another manufacturer and still getting the same problem.
I'm now with a Windows Vista, widcomm drivers (so weird too, because the wcl say I have the baMicrosoft stack)
Ok, reading again my post, Im not sure if you will understand it