You can select the icon and select Icons -> Information from the WB menu to make sure. Not all programs rely on having large stack space, but if it says something like 4 or 8kb then you could always try to up that to a few hundred.
It's odd that it quits randomly, but if it does quit in a benign way without trashing the system then chances are it decides it's time to quit on its own. Perhaps it needs something that's missing? Dongle? Files? Try using SnoopDos to see what's going on.
I never used Lightwave btw, I'm just throwing some suggestions
