Sadly this may remain a mystery.
I solved the issue by simply recompiling the dll in question. Once I had done that, and registered the new version, the problems went away and it worked both in admin and non admin. I had an upgraded version of one of the components in the .net project and perhaps updating that resolved the issue. I've no idea.
But life is good and coding can resume!
Sigfried Trent, aka FoxMan
(Working from his secret code cave, FoxMan battles the forces of darkness lead by the deranged and mysterious Bug Boy)
