Thank you, Don for your help.
I also have two more MGX 8850 with the exact same configuration, sw versions, cards and card fw. The RPMs on the other two MGXs did not cause me any problems upon upgrading, though. I cannot upgrade the MGXs (due to higher powers!!!). I did try to change IOS to the RPM, according to your post. Unfortunately, no luck!
I guess that leaves me with the MGX upgrade...Or an RMA possibly?!?!
Once more, thank you for the input.
Angela