Fix buglet introduced 6/2/13

Need to handle empty calFileName (thanks to MS for identifying the problem and the fix.

Signed-off-by: David Brainard <brainard@psych.upenn.edu>
Fix buglet introduced 6/2/13

Need to handle empty calFileName (thanks to MS for identifying the problem and the fix.

Signed-off-by: David Brainard <brainard@psych.upenn.edu>