Trying to backlabel tracts on a label volume with two versions of slicer (in DTi module):
slicer2.7-opt-linux-x86_64-2007-04-20
slicer2.8-dev-linux-x86_64-2007-08-02

I generated some tracts and chose the tab "vox" in the dti module. There, I chose a brain mask as a labelmap, and hit 'color ROI from Tracts'

this is the error message I get:
invalid command name ""
invalid command name ""
while executing
"$output GetScalarType"
(procedure "DTMRIVoxelizeTractsColorROIFromTracts" line 50)
invoked from within
"DTMRIVoxelizeTractsColorROIFromTracts"
invoked from within
".tMain.fControls.fWorkspace.fDTMRIVox.fBottom.fApply.bApply invoke"
("uplevel" body line 1)
invoked from within
"uplevel #0 [list $w invoke]"
(procedure "tk::ButtonUp" line 22)
invoked from within
"tk::ButtonUp .tMain.fControls.fWorkspace.fDTMRIVox.fBottom.fApply.bApply"
(command bound to event)