You’d get this message if your input data contains a DW gradient table, but the number of entries in it doesn’t match the number of volumes in your DWI file (here’s where it comes from). This would be confirmed using mrinfo, e.g.:
mrinfo ./Downloads/anger/anger_mrconverted.mif
if that reports a different number of volumes than entries in your DW scheme, that’s the problem. For a well-formed input, this should look like:
Dimensions: 104 x 104 x 54 x 167
...
dw_scheme: [ 167 entries ]
Assuming that’s the problem, it’s difficult to help without knowing the particular of how your input DWI data were produced…