converting 3d nii to 4d

[batel yifrah]

Hi,

I am trying to convert my nii files from 3d to 4d. 

When I am choosing 'single data set conversion', I can choose only one nifti file instead of my 71 files. 

When I am choosing 'muitiple data set conversions'  it tells me I have the wrong num of DWIs (although I inserted the exact num of gradients like my nii files).

I will be very thankfull for your help,

Batel