Good hear you got it working.

>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!