Are you sure you use the current version ? If not, download and install the full GSX installer now, and don't use an earlier installer you might have downloaded in the past.
If you are sure you use the latest version, the most likely cause for a crash while regenerating the cache, is a corrupted .BGL. If you enable error logging in GSX, you might be able to get a diagnostic of the related file.
You can enable logging without being able to access the GSX interface, this way:
open the Notepad and type the following on a new blank file:
logFile=couatl.log
(please note logFile is written beginning with a lower case l and a capital F )
Save the file as couatl.ini in the %APPDATA%\Virtuali folder, run FSX and then exit after it finished loading. Check your %APPDATA%\Virtuali folder and if there's a Couatl.LOG file there, post its content.
