AlignSets.py fatal error in write() command (with core dump )

Here's the relevant part of the traceback from python (not sure what the issues is with my input file)

sys.stderr.write('Error processing sequence set with ID: %.\n' % data.id) ValueError: unsupported format character ' ' (0xa) at index 41

in case you want it, dumped core posted to: s3://AbVitro_Kleinstein_shared/debug/AlignSets-muscle.ST-20150204.core