Yeah I think you may have been right, it was my own cache causing the problem.
Thanks folks.
BTW I have one last question, when there are new upgrades of UBB say from 6.2.1 to 6.3.0.1, or soon 6.3.0.1 to 6.3.1 do you have to go through all the hack updates again?
I recon you have to, but I'm hoping someone has a great suggestion on a quick way to do it!
(I do have multihack installed, but it still takes a while!)