Hello Mimi,
Did you already try to change the matrix solver in process settings?
As I could understand you have AMG solver on, and the message error said that "AMG solver not being able to solve".
So, try to change the matrix solver to another one, for example, automatic.
I hope that this will help you...!!!
Eng. Gonçalo Rodrigues
MOLIPOREX,S.A.
Portugal