Crash to Desktop/Server on every Zone or Most Zones.
The UserData folder is holding a series of journalled entries.
In most cases, a corruption has been introduced that is causing the Crash On Zone. Seems that these files are read when you zone.
The Fix:
1) Navigate to the Everquest Folder and locate the UserData folder.
2) Delete the contents of this folder.
3) When you log back into EQ, do an ALT-J and uncheck the Journal Logging feature.
4) Should be good to go from then on out.