make sure that there is nothing in Classic that is running, other than the Finder.
If the problem still exists, you may have to start playing with the extensions in System 9.2.2 using the Extensions Manager.
Unfortunately, it is all trial and error
I replaced my printer for my eMac and now Classic (OS 9.2.2) has a printing problem. When I open the Chooser and select the printer (Epson SC740) a message appears that "the printer port is unavailable because another application is using the port". I deactivated Apple Talk to make sure that this is not the problem but the same message appears.
OS 10 has no problem printing.
The port should come up as USB Port 1 as it does on my iMac. How do I find the application referred to so that I can close it or whatever?