Can't open certain modules

For some games, such as Elder Signs, the program works fine, but for others, specifically 40k and Star Fleet Battle Force, I load the module and then VASSAL crashes, this issue seems to persist regardless of what version of VASSAL I use, any ideas on what might be going on here?

Cannot comment on 40k as it is not available but have no problems at all with Star Fleet Battle Force. Works just fine.

Can you post your errorlog so we can see what is happening?