Error Code 144

Hello all, new to the forum, so I would like to say thank you in advance for any help I may receive.

 I have been using CPS8R elements to model a plane stress problem, in conjunction with a UMAT I have developed. This has been running correctly, and the results obtained are good.

I am now running an analysis using axisymmetric elements, CAX8R.

The output from CAX8R is..... S11, S22, S33, S12. The ouput from CPS8R is....S11, S22, S12.

I have therefore updated the damage model accordingly to account for this.

I have run the axisymmetric model without my UMAT, and it works correctly. But when ran with the updated UMAT, error code 144 is displayed. It runs for 1 step, before failure and the error message.

I assume the problem lies within the UMAT itself, however I have used the same priniciples as I have done previously for the plane stress problems, but extended it to monitor the new outputs.

Is this a common problem people experience? Any advice on the likey cause of the problem, as well as any advice on how to solve it would be brilliant.

 Thanks for your time,

Michael