Hi!

I'm Danilo Mattia, technician of the BCI laboratory at the Santa Lucia 
foundation, Research and Rehabilitation Hospital, Italy.

I turned my T1 T2Flair and lesion nii files into mat files with the command
'nii_nii2mat'for each of my subjects.
I would now like to create a single .mat file with the 'nii_merge' command.
 However, when I start this command I am not asked for the .mat files,
as it is written in the 'introduction to NiiStat',  but for the .nii files.
When I run the command with the .nii files I get this error;

Output argument "v" (and maybe others) not assigned during call to "nii_merge>vReadSub".

Error in nii_merge (line 24)
    val = vReadSub(nameVal, size(img,4), 1);

I would like to know what my mistake is and how I can fix it.

thanks in advance for your help!
danilo