Dave Winer of Userland Software:

Dave Winer of Userland Software: Ominous words from Steve Zellers for all developers who use AppleEvents (like us). “A future release of the AppleEvent Manager in OS X may break some applications.” Oy.  [Scripting News] [Mac Net Journal]

You must not use AEGetDescData or AEGetDescDataSize to extract data from an AERecord or AEList. Trying to do anything with the dataHandle of a desc that contains a list or a record will result in Very Bad Things. Use the AEGet* APIs to get the data from a record or list.

Guilty! I’ve done that in System 7 Pack. oy! is right.