[Freesurfer] FS-FAST "If: Expression Syntax" Error

Hi All, I'm running into an error analyzing some fMRI data with FS-FAST in Freesurfer version 5.3. The analysis runs fine until it gets to the register-sess part, which quits before actually starting to do any registration. The last line of the log file, attached, is "if: Expression syntax", but there are no other errors prior to that. The command I'm using, analysis, and contrasts have all worked on several other similar data sets. Has anyone encountered this problem before, or know what's causing it?

Thanks, Matt

Clinical Research Coordinator Stufflebeam Lab Athinoula A. Martinos Center Massachusetts General Hospital 149 13th Street, Room 1115S Charlestown, MA 02129