Error popup "Duplicate OWNER line in license file": We installed the license file sent by Synactive and now get this error popup.  What could be the reason?

A bug in GuiXT versions 2014 Q1 1 - 2014 Q3 1 leads to this false error popup, and the license file does not become active. To correct the problem either
  • Install GuiXT 2014 Q3 2 or above

    or
     
  • Use a special temporary license file sent by Synactive for this purpose together with the permanent one.