I did not know there was a PhotoBooth upgrade. I thought Leopard just had version 2.02 and that was it.
Anyway when something goes wrong, one wishes things were the way they were previously. Wishing aside, this is possible by restoring something from a backup, or in this case reinstalling the application from your Install DVD.
If you have Time Machine, you can locate the older version, select it and choose Restore.
It would also be possible to reinstall the older (if it does indeed exist) version of PhotoBooth from your Install DVD using
Pacifist.
And to avoid any problems in using it, read the documentation here:
Pacifist Documentation