Hi Paula,

This is a mystery. I can't see how VOI2 gets generated.

Can you try changing the following lines:
P.VOI.VOI = [maskpath filesep voiNAMES{jj}];
P.VOI.masks = masks;
P.VOI.thresh = threshold;
P.VOI.min = VOImin;

to

P.VOI = [maskpath filesep voiNAMES{jj}];
#P.VOI.masks = masks;
#P.VOI.thresh = threshold;
#P.VOI.min = VOImin;

and see if it runs. This changes the P.VOI from a structure to a file and calls different sections of code. This might help narrow down the issue.

Thanks,
Donald