How can I solve these errors in this .bvec-.grb converting tools?

Hello to everybody and thank you for your precious attention. I am a newbie in matlab using, so excuse me for basic errors. I am trying to convert a .bvec file into a .grb one with this code

>> g = dlmread('textfile containing gradients', ' ');
>> g = g';
>> grb = BVQXfile('new:grb')
>> g(:,3) = -g(:,3); %polarity change of z-component. CHECK this!
>> grb.Gradients = g;
>> grb.NrOfEntries = length(g);
>> grb.IncludeBValues = 'no';
>> grb.SaveAs

if in 'grb.IncludeBValues' I set 'no', it works; if I put 'yes', (and I need it), it doesn't work and gives me this errors:

Error using aft_SaveAs (line 153)
Error saving file : ARRAY dimension mismatch..

Error in xff/subsref (line 203)
                            [varargout{1}] = feval( ...

How can I solve it? Thank you very much.