I was having an issue where I could not assign printer driver profiles
to existing printers. I did not find a complete answer anywhere so I
am posting this after resolving my own issues with some help from this
forum and the ipint forum.

I was running NW 6.5 sp3 with Imanager 2.02 I had applied
Imanager Maintenance Updates:
iMan202_3_20040513
iMan202_5_20050302

I could not make use of printer driver profiles without crashing
Imanager and getting an error 500. A quick way to reload Imanager
follows
JAVA -EXIT
AP2WEBDN
tc4stop
TCADMUP NOTE: watch logger screen and wait until loading completes
TOMCAT4 NOTE: watch logger screen and wait until loading completes
AP2WEBUP

My issue was resolved after applying Iprint updates
iprntnwpcsp12b and
iprintjar3

NOTE: you must create printer driver profiles from IE but you can
assign them and manage printers fine with Firefox after you have made
all your printer driver profiles and assigned them to printer drivers.