Fatal Erron when Plotting

We are currently experiencing an interesting new situ in our AutoCAD
2000. It happened today during the Plot operation. We had a drawing up
on the screen, clicked the Plot icon, selected Tabloid 11x17, Scale
1:1, Extents click OK - all just like normal. The Plot Progress window
came up like normal, then an AutoCAD Error Aborting window came up. It
says "FATAL ERROR: Unhandled c0000090h Exception at 3398cb55h". If we
go back and change the Tabloid 11x17 to Letter 8-1/2x11, and that's
the only change, it will print fine, on an 8-1/2x11 sheet. We
discovered this situ today when we created a new "B" sized print and
tried to Plot. Upon experiencing the problem we started trying to plot
other proven "B" sized prints. This appears to be happening on all our
"B" size prints. Our "A" sized prints Plot fine as do our "B" sized
prints only after changing to Letter in place of Tabloid. We'll
probably just uninstall and reinstall. So far, that's the one fix-all
that always fixes all - hope it does this time as well. It is a
mystery though. What do you spose we have done to cause this? All
ideas and comments will be greatly appreciated. Thanks, K.