I have managed to track down the var. responsible for button redirects.
It is strUrlToReturnTo. This seems to equal 'parentfolder' but the redirect
always fails. I have rewritten the redirect to use the 'fall back' value,
which for the majority of cases has worked. The only page  it wil lnot work
for is the create subscriptions page, for which I used histroy.back from
javascript. There's are still some tweaks needed for it all to work though.
There's a major problem with the error  return handler as well. I might have
to go thru the included tahoeutils.asp to amend the global function that
produces the strURL... variable...urgh...

I still don't know why this var is causing an error.
It is definitely not null (as I say it is = to 'parentfolder'). Does anyone
know why this link is throwing up errors? please refer to mail below for
context.