Steve Dagley at Netscape notes the following Mac OS 9 issue with Netscape Communicator:
"There is a problem under Mac OS 9 with the Full Circle Talkback Quality Feedback Agent which is used to gather information about any crashes that occur while running Communicator. Part of this information is what files were opened when the crash occurred. Since this list is created by directly accessing the Mac OS FCB data structure a crash will occur under Mac OS 9 due to changes Apple made in Mac OS 9. This crash on access is actually a Good thing as programs that make assumptions about the old FCB structure format while accessing the new FCB structures can do Bad things. To avoid the problem, people updating to Mac OS 9 should remove the Talkback folder from the folder Communicator is installed in. As of Communicator 4.6 Talkback isn't installed by default but folks that updated from the 4.5 release may still have it installed."