Hi Mate,
Thanks heaps for the reply!
I was using the sa account, so I don't think permissions are an issue - happy to be told otherwise.
I found this article the other day which explains a similar problem (better than I have) but didn't seem to solve it.
http://support.microsoft.com/default.aspx?scid=kb;en-us;827448&Product=sql2k
This article doesn't seem to mention functions, perhaps that the difference?