If the error still occurs with Slicer >= r18444, please include content of error log.

Steve file list :
Administrator@JOE /c/cygwin/tmp/Slicer/EMSegmentTaskCopy
$ ls
CT-Hand-Bone/ MRI-Human-Brain.mrml
CT-Hand-Bone.mrml MRI-Human-Brain.mrml_remote
CT-Hand-Bone.tcl MRI-Human-Brain.tcl
GenericTask.tcl Non-Human-Primate/
Human-Eye/ Non-Human-Primate.mrml
Human-Eye.mrml Non-Human-Primate.tcl
Lesion-Exp.mrml Registration_ANTS.tcl
Lesion-Exp.tcl Registration_BRAINS.tcl
MRI-Human-Brain/ Registration_CMTK.tcl
MRI-Human-Brain-Exp.mrml Registration_DEMONS.tcl
MRI-Human-Brain-Exp.tcl Registration_DRAMMS.tcl
MRI-Human-Brain-Full-Parcellation/ Registration_plastimatch.tcl
MRI-Human-Brain-Full-Parcellation.mrml Template.tcl
MRI-Human-Brain-HIPR.mrml Test-Atlas-Cluster.mrml
MRI-Human-Brain-Hemisphere.mrml Test-Atlas-Cluster.tcl
MRI-Human-Brain-Parcellation/ vtkCTHandBoneClass.cxx
MRI-Human-Brain-Parcellation.mrml vtkCTHandBoneClass.h
MRI-Human-Brain-Parcellation.tcl*

Updated EMSegment/Qt/Py/EMSegmentWizard/EMSegmentSelectTaskStep.py to provide further output and possibly solve issue -waiting for additional output from Steve

Steve confirmed the bug on Nov/01 on an win XP x64 machine and win32 build. He was able to run EMSegment Fast which means that Generic.tcl is correctly loaded

Steve> Task names and task files in some kind of a list that is separated by the ":" character -- but on windows the ":" is an integral part of an absolute path, so your call to 'split' is giving you something you did not expect.

A quick fix could be to use ^ as a separator.

To validate a task filename, you could also count the number of "separator" and make it doesn't contain any.

Checked in possible fix

Slicer3: r16900
Slicer4: r18570

This bug appeared not to be fixed unless a fresh build was done. This was due to moving the install location of the python files such that the older un-fixed versions were still being loaded.

see steve's last note