Disable the auto update if you are using an older revision of the editor. Dirbaio has rev 309 marked as stable now. But for older revs, go into the editor and make sure auto update is not selected for the DB. Then, modify your spritedata.txt. Delete the two new "mystery sprites" 324 and 325 at the bottom. The editor will now open.

yea, but the recommended thing is to update to r309. It's perfectly usable now, I reverted temporarily all the changes in r303+