Nabla - thanks for the report!
This issue makes the game crash so it's quite serious.
Can you please specify which version of the game you were using, and include
the complete output of the game when it starts? Please also mention your
platform (Windows, Linux, etc.).
If you can readily reproduce the problem, perhaps you could attach a savegame
that would enable us to do it. A backtrace from within GDB would be appreciated
if you know how to get one.