thank all of you kindly reply. there no more information about the error , just as I show you above. I just put the avdd as a varible value , then change the power avdd from 3.0v to 3.6v ,use a linear fashion, step 0.1v , then just can run sweeppss-000, that's mean just run avdd=3.0v,then it can't run the second avdd=3.1v and so on.
I use even more older version spectre , it can run the pss sweep correctly.
recently I don't plan to update new version mmsim 7.2. thank you!