The QubeGUI Preferences allows one to specify the external viewer to use. By default it will launch the application associated with the file extension and pass it a list of the files. However one can specify the executable as well as the options to pass into it. There is tooltip popup help if you mouse over the items in the QubeGUI Preferences.
FrameCycler expects certain options. Here is an example for setting the preferences.
Image Viewer: c:\Program Files\IRIDAS FrameCycler Professional 2007\bin\FrameCycler.exe
Image Viewer Options: Q[ %(file)s %(start)s-%(end)s ]Q
Look for "Image Viewer Presets" in the next release to assist with this.