Several users have reported, and I can verify, that an AppleScript routine used to apply image data to a track as artwork fails with an error -206 when used on iTunes 10.2. Essentially, the error is tripped when the following code--or similar--is run; theTrack is a reference to an iTunes file track and thePictFile is a valid PICT image file:
set data of artwork 1 of theTrack to (read (thePictFile as alias) from 513 as picture)
There are a couple a scripts here that use a variation of that (Re-Apply Downsized Artwork is one) and thus they will error when run with iTunes 10.2. The snippet works fine in versions before 10.2. I can use it on v10.1.2, for example. It might be a bug so I'll keep my eye on this.