I dl'd the 4.04 version of Communicator (standard) this weekend and could not get it to run. I chose an "easy install" and installed with no extensions. After restarting, I tried to run it and got a "memory address error" with a restart button. Tried again, same thing. Using Extensions Manager, I went to a base Mac OS 8 installation and added only the OT/PPP 1.1 components, restarted, and again got the same error.
This error is happening after the start up splash screen reads "Reading Preferences" so I decided to remove my old preferences by Stuffing them, moving the original to trash, and emptying the trash. Again, same error at startup.