Blender Traceback error when importing rig with the addon

So, I’m trying to make an arms rig, but when i imported the rig to blender to animate, it showed a traceback error

. It still imports though, but when I try rebuilding the rig, the same error shows up and it doesnt rebuild it. I tried with 2.79, 2.8 and 2.9 but still the same error. I searched everywhere for this, and none helped. Its the RBX rig addon thing.

@0003379 I am having the same issue, Blender Traceback Error when "Rebuild rig", did it get resolved?

I’m having the same issue.