NAV on XP in VMWare Guest under linux flashing screen when main app loads

I am runing Norton Antivirus 2012 on a Windows XP VMWare virtual machine with a host using VMWare Workstation 7.1.5 running on Ubutntu 10.10.

 

When I open the main NAV application window, the Windows XP screen starts flashing entirely black at random timing and durations.  The flashes happen at sub-second intervals and last a fraction of a second to several seconds.  They continue as long as the main NAV application is open and for several seconds after I am able to get to the X to close the window.

 

This virtual machine had been running under a Windows 7 host and I just switched to the Linux host and started getting this issue.

 

Any help would be greatly appreciated.