If you are still getting the same error, we would need you to send additional debugging information to help you further:
- When the error appears, do not close it: open a Linux terminal, then zip the openmeeg temporary files (tar zcvf debug_openmeeg.tgz ~/.brainstorm/tmp)
- Upload this .tgz file somewhere (eg. dropbox, google drive…)
- Post the link to the file here