I'm not sure why this thread is marked "Solved" because it isn't in my case.
I had a "double problem" -- I replaced the battery in my Tungsten C since it was having a hard time holding a charge. While I was fiddling with that, I decided that I would update my iMac to 10.4.7. Anyhow, after a good deal of fiddling, I got the Tungsten C back in action. I then put it in the cradle and began to sync. It ran more or less like it always has, although Hotsync Manager was crashing at a certain point each time. No big deal -- I removed the problem files, and it synced all the way through nicely.
The problem began later on, when I tried to sync again to update my prescribing reference software, which sometimes seems to need two syncs to work. It wouldn't work. Hotsync manager was simply not coming up. I know that my Mac was "seeing" the PDA because HardwareGrowl would notify me that it saw the PDA when I hit the sync button, but HotSync Manager didn't want to launch. Checked that it was running, downgraded back to 10.4.6, zapped PRAM, tried different USB ports...still nothing.
So why did it work initially and now not at all? I'm terribly frustrated tonight and have no idea why it isn't working... 😟
iMac G5 20 2.0GHz Mac OS X (10.4.6)