I think onemorebicycle is on to something here!
Got home, swapped out the batteries for a set of new, freshly charged NiMH batteries.
1. Inserted batteries in spokePOV
2. Plugged in 10-pin cable to spokePOV
3. Plugged USB dongle into laptop (yes even the Windows Vista laptop appears to work so far!)
4. Waited patiently to make sure Windows recognized the device
5. Hit connect
This method worked for both my spokes. I haven't tried loading an image on yet, but I was able to read several different banks and verify them seemingly without problems. So excited! Will let you know how things go from here.
Thanks for taking the time to check things out and help troubleshoot!