This is the part that contains the warning:
WARNING: no main driveline defined, adding dummy driveline
Traceback (most recent call last):
File "/home/[user name]/blender-2.63a-linux-glibc27-i686/2.63/scripts/addons/stk_track.py", line 2288, in execute
savescene_callback(self.filepath)
File "/home/[user name]/blender-2.63a-linux-glibc27-i686/2.63/scripts/addons/stk_track.py", line 2235, in savescene_callback
exporter = TrackExport(sFilename)
File "/home/[user name]/blender-2.63a-linux-glibc27-i686/2.63/scripts/addons/stk_track.py", line 2216, in __init__
lChecks, lSun, lDrivelines[0], lStart, lEndCameras, lCameraCurves)
File "/home/[user name]/blender-2.63a-linux-glibc27-i686/2.63/scripts/addons/stk_track.py", line 1995, in writeSceneFile
self.writeChecks(f, lChecks, mainDriveline)
File "/home/[user name]/blender-2.63a-linux-glibc27-i686/2.63/scripts/addons/stk_track.py", line 1538, in writeChecks
strict_lapline = mainDriveline.isStrictLapline()
AttributeError: 'NoneType' object has no attribute 'isStrictLapline'
location:<unknown location>:-1
location:<unknown location>:-1
^[OF