OWA user cannot open email folders

I have a user in the Canary Islands on vacation. Instead of enjoying his vacation, he is trying to read his email. He can log into OWA successfully. I watch my Firewall logs and the traffic is accepted. He can even see his folders and number of email. Then he claims it all fails, asks for him to log in again – then errors: You do not have permission to view these folders. We have talked him through disabling the Firewall on his XP SP2 laptop. We had him add our site to his trusted sites in IE and lower security settings. Any suggested would be greatly appreciated.