Seems like the same error as here.
The 2D classification files must drop the micrograph names. You should be able to add a .cs file from earlier, say your extraction job, that definitely has the names. I’ll be double checking this later, if it’s a missed field on my end.
Also, there was a bugfix last night so the error won’t occur, however the output .star file will be missing the micrograph names. Depending on what you needed to do, this might be OK.