Outlook Web Access (OWA) moved mailboxes onto new server

Hi, we have recently moved our mailboxes from our exchange server to a new mailserver, i cannot for love nor money get the outlook web access to run on the new one whether internally or externally, it still runs fine on the old one, all i get is page cannot be displayed, i know a little so you can rule out incorrect ip address or anyhting as daft as that (he says confidently!) Both are Win server 2003 Standard.
help Please!!!