Many thanks for the helpful replies everybody.
As soon as I get a chance, I'll snapshot the error and include some version information. I'll also try using the SM50 logon trace, and check out that other SCN thread. Unfortunately I'm completely tied up in other things at the moment, and this (while mildly irritating) isn't top priority, so it may be a little while before I have the chance to do so though.
But again, many thanks everyone, and I'll update this thread as soon as I've had a chance to try your helpful suggestions.
Cheers,
Tris.