I am using the trial version of PDAnet for my Palm Treo 650 and have yet to get it to work. I purchased a Kensington USB Bluetooth adapter and inserted it into my laptop, which is running Fedora Core 6 (a popular Linux distribution). There I start up the Bluetooth manager in "discoverable" mode and attempt to launch PDAnet from my Treo. The application "sees" my laptop's bluetooth adapter, but fails to connect with the error "Unable to establish connection with your PC (code=780)." If I try it enough, I'll eventually get an error code of "666", and the instruction to turn off the phone. The errors persist when I do so. The same is true when I soft reset the phone. Please let me know if I can provide any further diagnostic information.