thanks for the response.  I performed the steps you recommended. Its pretty clear you've got a lot of experience with troubleshooting other people's Matlab problems; even I was able to follow the steps. I'll include the output below. 

Some additional information that may or may not help:
-Today, I upgraded to Yosemite OS recently and consequently had to download and install Matlab2014.
-The output below indicates a problem with meanu001_mod.nii . The mod indicates that I had previously modified the image header to cut off the tail end of the scan. 

Michael


>> dbstop in spm_normalise at 153

------------------------------------------------------------------------
Running job #1
------------------------------------------------------------------------
Running 'Normalise: Estimate & Write'
Smoothing by 0 & 8mm..
153 VF1 = spm_smoothto8bit(VF,flags.smosrc);
K>> disp(char({VF.fname}))
//Volumes/MICHAELKING/Handgrip Data/2014 Analysis/Task Analysis/PPI Analysis Task Failure/001/PLA/meanu001_mod.nii
//Volumes/MICHAELKING/Handgrip Data/2014 Analysis/Task Analysis/PPI Analysis Task Failure/001/PLA/meanu001_mod.nii
//Volumes/MICHAELKING/Handgrip Data/2014 Analysis/Task Analysis/PPI Analysis Task Failure/001/PLA/meanu001_mod.nii
K>> dbcont
Failed 'Normalise: Estimate & Write'
Field reference for multiple structure elements that is followed by more reference blocks is an error.
In file "/Users/Michael/Documents/MATLAB/spm8/spm_smoothto8bit.m" (v4310), function "smoothto8bit" at line 33.
In file "/Users/Michael/Documents/MATLAB/spm8/spm_smoothto8bit.m" (v4310), function "spm_smoothto8bit" at line 16.
In file "/Users/Michael/Documents/MATLAB/spm8/spm_normalise.m" (v4621), function "spm_normalise" at line 153.
In file "/Users/Michael/Documents/MATLAB/spm8/config/spm_run_normalise_estwrite.m" (v4152), function "spm_run_normalise_estwrite" at line 22.
The following modules did not run:
Failed: Normalise: Estimate & Write