2.1 upgrade crashes during library file conversion

I tried upgrading from 2.0.7 (v10915) to 2.1 Beta (v11409), which is the advised route to work around Exception 10 crashes when using Publish (see link below). Unfortunately, when trying to start it for the first time it attempts to convert my library from 2.0 format to 2.1 format, and crashes with the following error message:

!
Operation could not be completed. Due to an internal error (Uncaught system exception: signal 10), I cannot upgrade your library file at '/Users/greg/Library/Application Support/Delicious Library 2/Delicious Library Items.deliciouslibrary2' from version '2.0' to version '2.1'. Your original 2.0 file has been unchanged, but Delicious Library 2.1 cannot continue.
OK

Any advice on how to debug/diagnose/work around this?

(I was upgrading to 2.1 beta to work around the Exception 10 crashes when using Publish, per the advice in posting "I'm unable to publish to mobile me after newest software update.")