mesh plotting does not work on Windows 7

I upgraded my PC to Win 7 (from XP) and installed MathCad with the 14 upgrade. I find that my programs having mesh plots no longer produce a plot-just a blank page. (Countours still work). After a little checking it appears that Win 7 is not mentioned as a supported platform for MathCad 14. I tried to call the support center but I guess since PTC took over there is no longer any support for Mathcad flaws and install issues (other than for a fee). Has anyone done mesh plotting with Win 7? Thanks, Fritz