Hi freesurefers

I tried to visualize my functional data using the  command: tkregister2 --s  --reg  --fslreg  --surf orig --tag

and i received this error :

ERROR: trying to convert FSL registration matrix to FreeSurfer,  but FSLOUTPUTTYPE variable is not set.

Can anyone help me with this ,

Thanks in advance , best regards.

--
Ignacio