Hello. I’m sorry about the late response. The reason this has happened is most likely that DWIConvert is not properly handling your diffusion MRI scan. We have a new module that will be available to use the DCM2nii tool within Slicer. This will become available in the nightly build version of Slicer. However, there have been some internal code updates to Slicer so we need to adapt SlicerDMRI to these for it to become available again in the nightly.
In the meantime, it is possible to use the software dcm2niix to convert from a large variety of DWI DICOM files to nifti and now also nrrd formats. Please see more information from Chris_Rorden here: