Could be indeed the problem.
Make a copy of file openjk.cfg :
cp /Users/username/Library/Application Support/OpenJK//MBII/openjk.cfg /Users/username/Library/Application Support/OpenJK//MBII/openjk.cfg.bck
Then trash it :
rm /Users/username/Library/Application Support/OpenJK//MBII/openjk.cfg
Then...