I am trying to use the [P.ConcatR = 1] parameter in gPPI toolbox, but I continue to get an error that the matrix dimensions do not match when running the spm time series extraction. When extracting the time series, "y" is not equal to the total number of concatenated volumes. 

For context, my first level GLM in SPM contains 6 different runs as independent regressors (with matching task and motion regressors per run). I also have predefined ROIs from retinotopy that are in the same space as the bold runs (MNI space). Instead of extracting the time series prior to using the gPPI toobox, I am using a .nii file for the VOI parameter which is allowed. However, it seems that the time series is not being extracted for all of the volumes and that the P.concatR is not working properly. Any advice on how to fix this problem? Should I concatenate the runs at the first level? Should I extract the time series prior to gPPI for the VOI and if so, what is the recommended method?