Hi Bryson,
I suppose you have the latest version SPM8, if not, update SPM 8 first.
Then check your data manually to ensure your raw data is fine:)
Finally you can try to process the failed data with SPM interface to
get the error message and send to me.

If it is still not work, you can send GRETNA log file to me.
It is at GretnaLogs, I will try to find what happened.

Best
Sandy