Getting error during free body forces

Hello,

I am trying to extract the free body forces in optistruct.

I defined the elements using a set name “FBD CXX”.

And check these values in Global output request card.

GPFORCE.

FORMAT OUTPUT2

OPTION ALL.

And after running the simulation, I am getting this error.

Would you know how to solve it?

Thanks and Regards,

Sanjay