Abaqus matlab interface, invalid frame index

I am running python scripts of abaqus using matlab. it runs fine until the 4th iterative loop and shows the error "INVALID FRAME INDEX". I dont understand what should i change in my python script. could you please help me?. And also I have the Output report file generated. Is there any way i can directly take the output to Matlab or should i extract from the rpt file. Please give me hints. Thanks