You should be using ADTPro with your more recent computer.  Connect a serial cable or from your computer to your Apple //c's serial port, then follow the directions.  Alternatively, you can even use the audio port if you don't want to deal with serial connections.

If you want to use your SE/30 just because it's fun, then you'll need to track down a copy of the original ADT for System 7.  Hopefully someone better at Google can find it (or if they have a copy, post it.)  Works nearly identically to the most recent version.