Dear FreeSurfers,
I'm trying to perform First level analysis using "selxavg3-sess -sf sessid -analysis color.sm0.mni305". However, the analysis was interrupted by the following error.

... ...
Smoothing ACF
/usr/local/freesurfer/bin/mri_fwhm --mask /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/mask.nii.gz --i /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/rho1mn.nii.gz --o /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/rho1mn.sm.nii.gz --fwhm 20.000000 --smooth-only
voxelvolume 1 mm3
Loading mask /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/mask.nii.gz
ERROR: no voxels found in mask

ERROR: /usr/local/freesurfer/bin/mri_fwhm --mask /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/mask.nii.gz --i /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/rho1mn.nii.gz --o /media/bob/DATA/FreeSUBcolorv2v4/functional01/Sess01/bold/color.sm0.mni305/rho1mn.sm.nii.gz --fwhm 20.000000 --smooth-only

ans =

     1

I also loaded the mask and found that all the values are 0. 
I finished mkanalysis-sess and mkcontrast-sess without error. Is there anything possible wrong in the previous steps when generating the mask?

Best,
Bob