Are you on Single Player? If so you now have to ascend to access the Center and Ragnarok. Bring up the admin command bar and type one of the following three:
playercommand Ascend1 (GAMMA)
playercommand Ascend2 (BETA)
playercommand Ascend3 (ALPHA)
to ascend to the different levels. If you do the alpha one it unlocks all three. Gamma will get you onto the Center, Beta onto Rag I think