Go to Altsettings.prop and find this line :
# ConfigClassMaster=1;[];[];2;[];[];3;[];[]
# 1st, 2nd, 3rd occupation change for free, without rewards
ConfigClassMaster = 1;[];[];2;[];[];3;[],[];[]
At the ConfigClassMaster, you probably got False, so you just put what I got, if you set it to true, the GS will error out, because that is not a config, it's a statement. Enjoy!