This is the error message I get after the 4th step. The steps 1 to 3 converge.

The value of UX at node 61017 is 131036267.  It is greater than the    
 current limit of 1000000 (which can be reset on the NCNV command).     
 This generally indicates rigid body motion as a result of an           
 unconstrained model.  Verify that your model is properly constrained. 

I tried a static analysis before and it worked fine, so I'm not sure why there should be a rigid body motion.