Could you alo package an example dataset for us to test?
- Duplicate the subject for which you are getting this error (right-click on the subject folder > File > Duplicate subject)
- Delete all the files that are not necessary to reproduce the error (both in the anatomy and the functional sides of the protocol, keep only the MRI, the head surface and the cortex surface that is selected), to make the file easier to share
- Right-click on the subject > File > Export subject
- Upload the .zip somwhere (eg. dropbox) and send me link by email (click on my username on this forum)
I will repackage the data so that it can be tested easily with different versions of OpenMEEG.