HELP! Summation/Integral symbols show as ? in FM8

[Charles Grinnell]

When using FrameMaker 8.0p277 (Windows XP), larger symbols (such as Summation and Integral) in equations appear and print as question marks. 

The problem applies to new equations and to existing equations that display/print correctly in FM 7.2. 

When searching the web for info, I found similar reports relating to the FM8.0 trial version, but no suggestions for fixes/workarounds.

Is it possible that this bug has not been addressed since? Anyone successfully using FM8.0/Windows with equations? 

Help appreciated, thanks in advance!

Charles