Treo 650, bluetooth hotsync problems

Archived from groups: alt.cellular.bluetooth (More info?)

Having trouble syncing my Treo 650 via Bluetooth. I have:

Treo 650
TRENDnet TBW-101UB Bluetooth USB dongle (two of them, for my two
desktop systems)
Billionton Compactflash Bluetooth adapter (for notebook, works fine
with Bluetooth mouse)

On all three machines the Treo and Bluetooth adapters can see each
other including each others' device names. When trying to sync, I
always get the error that the "port is already in use by another
device" or somesuch nonsense. I use a Bluetooth-mapped serial port for
this and have verified that Hotsync is pointed to the correct COM port.

Am at my wits end. I suspect this has something to do with Windows XP.
The two desktops are running XP Pro sp2, the notebook is running XP
Home sp2.