FFXI-2003 Can't read data/no Zilart expansionFollow

Running a system that, a year ago, could handle FF XI. It displays the graphics I can access just fine, but I'm getting error FFXI-2003 whenever I try to log into the game. (select character, downloading data, you can see the chat windows start to pop up and then it gives the error message and goes back to POL.) I've installed Zilart, uninstalled and reinstalled both, and my content ID is registered with Zilart.

EDIT: The common fix for this is to disable antivirus software, but no dice. Exited out of everything (ending the individual processes) and I still get the error. On Windows XP or 2000.

Edited, Wed Jan 4 14:25:54 2006 by GeoMaximus

It was no big, my fifth reinstall :D It works now, thank god. I'm never touching those install CDs again if I can help it.