Hmmm...
I just tried it on my 300, and it works fine. So now we have the fun of trying to figure out what is going on for you.
First, I am not happy about seeing the message
Removing playlist id: 420 Purchased
twice in the log file. That implies that something went wrong with writing the media.xml file the first time around. Are you able to send books to the device and have them show up? Does the update timestamp on the file database/cache/media.xml make sense?
Putting the above aside (with some trepidation), lets start with the basics:
1: #disporder is actually a series column, not a composite column?
2: You have data in the #disporder column? If it is a custom series column, it should appear in the tag browser (left hand side), and you should be able to select values to search for them.
3: You should be able to sort by that column.
If all of the above is true, then we will need to go to step 2. I am not sure what that step is.
