In GameData run MBII_Beta_Setup.bat to import additional files from your MBII folder.
If you cannot run the batch file, manually copy these files from your MBII folder to MBIIBeta:
Code:
jampconfig.cfg and/or openjk.cfg
mb2_cloudcity.pk3
mb2_commtower.pk3
mb2_dotf.pk3
mb2_jeditemple.pk3...