ITunes displays a -50 error when syncing iPod

Question

When I sync my iPod with iTunes I get the following error message:
"The iPod cannot be updated. An unknown error occured (-50)"
I recently completed a fresh install of my library into iTunes (7.0), then sync'd my iPod. As it was a new library it did a new fresh install to my iPod, but now, every time I sync my iPod it gives me the above message.
Most notably my podcasts don't appear on my iPod now. I have all the latest updates. Can anyone help?
Powerbook G4, 867Mhz   Mac OS X (10.4.7)   640 DRAM

Answer 1

Its not clear what error 50 means. In another context it appears to be something to do with confused or lost authorisation for purchased files for that mac.
I had that problem - couldn't download purchased songs or play previously purchased ones. In attempting to play them, I repeated the process of "not authorised" errors, then being prompted to authorise, doing so and getting success messages only to fail again. Error 50 as the failure code.
Try playing some purchased music. Also try purchasing something (like the the free track of the week on the store home page). See if you get the same message.
I eventually cleared it - though not clear how. All I did was the usual trick of checking permissions, running the maintenance scripts (via Onyx) and rebooting a few times.