Could you check if the problem still happens with CS 1.4 branch ? ( http://www.crystalspace3d.org/trac/CS/wiki/Version14Plan
Because it's unlikely that any fix is devised/integrated into 1.2 now...
In case it still happens, make sure you build in debug mode, to give the the debugger a chance to provide more informations,
and consider creating a ticket on CS Track
(you should be able to log in with same account as for this forum)