Some of the newer Artwork Management scripts will fail in Mavericks. They each use a routine that dumps artwork to a file which doesn't work very well under OS X 10.9:
tell me to set fileRef to (open for access pathToNewFile with write permission)
tell application id "com.apple.iTunes" to write (get raw data of artwork 1 of theTrack) to fileRef starting at 0
tell me to close access fileRef
iTunes will give up an error like this: "AppleEvents/sandbox: Returning errAEPrivilegeError/-10004 and denying dispatch of event rdwr/writ from process 'Save Album Art to Album Folder' because it is not entitled to send an AppleEvent to this process."
(Two words I didn't want to see side-by-side: "AppleEvents" and "sandbox".)
The fix is to just stuff the raw data into a variable first then write the data to the file from the variable. I'll be working this fix into all the scripts affected over the next days and weeks.