Howdy-
Hmmm, OK. I ran the following in the Bootcamp data (AFNI_data6/FT_analysis/FT directory) OK, and got the attached image:
3dTqual -range -automask FT_epi_r1+orig | 1dplot -one -stdin -png NAME
However, if I ran without the extension:
3dTqual -range -automask FT_epi_r1 | 1dplot -one -stdin -png NAME
... then I got the error you are seeing:
*** Can't open dataset FT_epi_r1
** FATAL ERROR: Can't read from stdin!
So, whether your input is NIFTI or BRIK/HEAD format, can you try putting the more complete name: NAME.nii, NAME.nii.gz, NAME+orig, NAME+orig.HEAD, etc.?
--pt