ok I've re-read the thread

if you are using the method that sledger showed in his video then as others have said the following path in not correct:

c:\Program Files (x86)\Xara\Xara-Photo_Graphic_Designer_7\Xara Picture Edtitor\PSplug-ins\Downloaded Plug-ins\

you do not want your luce plugin in the Xara Picture Editor tree - if that is where it is then that may well be your problem [do not worry about why there is reference to this in the manual, that is for specific cases]

make a folder call it ' my downloaded xara plugins' or whatever meaningful unique name you want - put your luce 8bf file in this folder, put the folder at c:\ and then use sledgers method to set it up - it should then work; if not then I give up

EDit - oh and remove it from the c:\Program Files (x86)\Xara\Xara-Photo_Graphic_Designer_7\Xara Picture Edtitor\PSplug-ins\Downloaded Plug-ins\ location, don't leave a copy there