I started off with the difficult bits, these are things like queries that were doing calculations/lookups on the fly etc.
It all worked great.
I then got to the easier part, where I dragged a SQL datasource, dataset etc onto the form and bound it too some text/list boxes.
However, as soon as I ran it, the site wouldn't even go past the first page (the SQL datasurce control was on the 4th page)! I then removed the binding and found the site still didn't work! I located the problem to being a copy of the SQL database having been created. Once the copy was removed, the site ran fine.
I did this twice just to make sure, and it happened both times.
I really don't know what caused the problem, it was weird.
Do the standard data controls automatically create a backup of the data? Do the standard data controls open a connection as soon as the site starts? I always close the DB connection as soon as I've run a query so I think any connection conflicts must have been caused by the standard controls.