I have this exact same problem with both my iPod Classic (new as of late April) and my new iPhone 3G. I can't sync any photos at all and I get the error message "The [iPod or iPhone] cannot be synced. The required file cannot be found."
I called Apple soon after buying my iPod Classic, and all they could suggest was to bring it to a Genius Bar. I haven't had any time to do that, and after the ridiculous amount of time I spent in line last Friday I am loathe to go near another Apple Store again for the next five years.
Does anyone have a solution to this? I have reinstalled iTunes and trashed pref files, to no avail. I'm running 10.4.11 and have the latest updates for the iPod and the iPhone.
Thanks.