sry, this is slightly off-topic, too (yeah i realize you're in a business environment and you won't switch that easily...)
but, from a long-term perspective, i think you're much better off using latex (a reasonable setup on windows is miktex+winedt+ghostscript).
as for your actual problem, no real clue. i haven't used wordperfect in 8 years or so. as a novice to wordperfect, i would probably try to see if the problem goes away in openoffice (which can open but not save wordperfect files). otoh, only other idea is to try if adding mathtype
to wordperfect does any good.