For starters, you shouldn't ever post your admin password, and your launch command line should be
ucc server KF-BioticsLab.rom?game=KFmod.KFGameType?VACSecured=fa lse?MaxPlayers=6?AdminName=Pvt.Mason?AdminPassword =asd899rd?Mutator=MutKFAntiBlocker.MutKFAntiBlocker,ServerPerksMut.ServerPerksMut
you separate multiple mutators with a ,
Secondly, make sure your ServerPerks is updated, as the recent update broke ServerPerks, which will cause servers to crash when a kill is made.