RE: locked out!
The Digital Performer crash is caused by the lethal combination of Digital Performer 4.6, OSX 10.3.9 and any plugin compiled with the latest XCode (Apple development suite). If you use certain chunks of code, compile, and then run the plugin on Digital Performer 4.6 on Panther, <kaboom>.
Unfortunately, the latest XCode is required to get the apps in Universal Binary, and also gives a performance boost in PowerPCs.
It is possible that we might find a workaround for this issue, and it is also possible that those will be fixed in next Digital Performer release. However, I think the ultimate fix is updating OSX to 10.4.x. I know, it's a paid update so it's no good news, but it might help you to avoid issues in other plugins as well, now that everyone is moving to Universal Binary.
In the meantime, I think there's a way to reinstall without reinstalling the contents. I only remember the PC-side procedure though, Chad?