Dear Dr. McLaren,
I have encountered some errors when conducted ppi analysis.
My data was ER-design, 6 runs, 5 conditions. I have conducted first level analysis and got SPM.mat (with 32 contrasts).
The error was reported as: 
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Parameters used:
Processing subject: Sub29
VOI file : G:\Yan.X Projects\4_fMRI_Self_Suppression\RSA_ONE_SUB_20170622\Try_gPPI\GLM\Sub29_Sub29_R_hipp_23_-35_-2_radius_10mm_roi_cond_psycond_PPI_structure__psycond_PPI_structure_ 16-Nov-2017.mat
Output file will be: Sub29_Sub29_Sub29_R_hipp_23_-35_-2_radius_10mm_roi_cond_psycond_PPI_structure__psycond_PPI_structure__session#_cond_PPI_regressors.txt
Contrast : No adjustment
Analysis : Psychophysiological Interactions
Extraction : eigenvariate
Tasks : _1_Baseline_Retrieval Negative_Retrieval Positive _Suppressive Negative_Suppressive Positive
Method : Condition Specific
Program will exit. mat-file is not formatted correctly.
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I am not sure which mistakes I made, may be I did 32 contrasts in first level? or I just did use the same name in the contrast matrix?
Could you please do me a favor and look at the following code?
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P.Contrasts(1).left = {'Retrieval Negative'};
P.Contrasts(1).right = {'Retrieval Positive'};
P.Contrasts(1).name = 'Retrieval Negative-Retrieval Positive';
P.Contrasts(1).STAT='T';
P.Contrasts(1).Weighted=0;
P.Contrasts(1).MinEvents=5; 
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