Metadata transfer for existing songs generates error

I copied most of my music library from my iPod's library to a new computer, but I already had a few songs in my library via iTunes' built-in "Transfer Purchases" functionality for songs that were purchased from the iTunes Store.

In PodWorks 2.9.3's preferences, I've selected "Always" for the "Actively Prevent Duplicates" pop-up menu, and I've checked the "Transfer metadata only for songs already in iTunes". However, when I attempt to transfer the metadata for these files by selecting the appropriate songs on my iPod and clicking the "Selected to iTunes" toolbar button, I get an error message for each song.

Usually the error message says "-30720: Invalid date and time 2008-04-03 00:59." or something like that. I'm not sure what date and time it's referring to, though -- maybe the last played or last skipped time, because it's not the current date, and it's too recent to have been the date added. One song has the error "-10006: iTunes got an error: Can't set library playlist id 5260 of source id 39 to «class" and the rest of the message gets truncated by the Transfer Errors window.

Other relevant info: I run my system under the Italian localization (although PodWorks does not have one so it defaults to English, my next setting). I also have a non-standard medium-length time format set up in the International preference pane -- my time format includes the date via a trick (see http://www.macosxhints.com/article.ph... ), so maybe this is causing problems.

Any ideas on how to fix this problem? I want to transfer my metadata to my library before I set my iPod to sync with this new library.