Thanks for the responses. I did some checking on the Apple forum and found this interesting info, so I thought I would post this just in case others run acroos this issue:
You can boot into open firmware by holding the command _option _o _f _keys at startup. If it showsBuild date April 23, 1999 then you have the Firmware 1.2 which is latest version currently available from APPLE. If yours shows an earlier date you need the update. It is possible you may have a later version if you computer was serviced by an APPLE tech at some time ............. although I have not seen a later version on a 266 MHz iMac come across these forums. But it is a common occurance with the 333 iMacs.
The Firmware 1.2 will show boot rom version 3.0.f2 in the Apple System Profiler.
There has been much confusion about firmware and boot rom versions because a later firmware version for some tray-load iMacs will show boot rom version 3.0.f3 which is the same as what shows for a much earlier version of firmware. The best way to check is by looking at the build date. ------ Or --- if things are working properly you can attempt the 1.2 update and [if you have a newer version] it will give error and dialog box stating the firmware on this machine is not recognized.