But I have another question, in my SPM.mat, there are 12 beta images, from beta_0006 to beta_0012 was head movement regressors and constant, and each condition had its unique name. The error was reported as: 
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estimate_PPI.m
Estimation Failed
Warning: Missing conditions!!! Invalid Contrast
Invalid Contrast
Warning: Missing conditions!!! Invalid Contrast
Invalid Contrast
Warning: Missing conditions!!! Invalid Contrast
Invalid Contrast
PPI Contrasts were not estimated for some reason.
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Dose the SPM.mat for estimating cannot contain the head movement regressor?

Best,
Xinyuan