Problems using LOAD/PBLAST

Hello together,

i am traying to simulate the Load of an explosion on a steeldoor within a Frame of concrete. Unfortunately the Solver shwos the error "**ERROR : TIME STEP LESS OR EQUAL ZERO", but i cant find the Problem in the Model. Does somebody already used the load PBLAST and can tell me what i did wrong?

Thank you for any kind of help.

Best reggards 

Bennet