Need help with my script

I made this little script to detect the installed version of QuickTime on a system and depending on the result, jump to a specified marker. Now the script works fine in director, but when I create the projector file and run it, it came up with "Script Error" and ask whether to continue or not. Now it still jumps to the right marker when I click 'Yes' but I just can't stop that Error from poping up. Any ideas?

Here's the code:

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--Created by Lomi Paeniu 2003


property pRequiredVersion, pMarkerN, pMarkerY

on getpropertydescriptionlist me
  set description = [:]
  Markers = ListMarker()
  addprop description #pRequiredVersion, [#format : #float, #default : "",  #comment : "Required Version:"]
  addprop description #PMarkerN, [#format : #marker, #default : Markers, #comment : "Which maker to jump to if version is older:"]
  addprop description #PMarkerY, [#format : #marker, #default : Markers, #comment : "Which maker to jump to if the version is fine:"]
  return description
end  

on enterframe me
  pCurrentVersion = quickTimeVersion()
  if (pCurrentVersion < pRequiredVersion) then
    go to marker(pMarkerN)
  else
    go to marker(pMarkerY)
  end if
end

on ListMarker me
  plabelString = the labelList
  delete the last char of plabelString
  pmarkerCount = the number of lines of plabelString
  ptheFrame = the frame
  repeat with i = 1 to  pmarkerCount
    ptheMarker = line i of plabelString
    pmarkerFrame = marker (ptheMarker)
    if ptheFrame < pmarkerFrame then
      return ptheMarker
    end if
  end repeat
end
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I test it in Director 8 and MX. Both came up with the same problem.