I deleted the add-on now but i will have another go at it. I believe certain customisations cause it not to work although it seems only to be for interpreting the BBCODE somehow...
Never mind...
I got it working now by replacing some files (which differed from the originals).
Seems ok now but how do you add modules to the list which are not default pgpnuke modules?
Although so far I created sitemap.xml files, our google positions are fine. I thought about adding NukeSeo and I did yesterday but it doesn't seem to work although no errors are given anywhere...