Which browser. Is your macbook connected to the internet (can you google) what is the network you're running on (obviously the iphone and ipad can connect via 3G which is different to your macbook's connection) etc.
I have also had this issue. I suspect that it is related to cookies and/or browser settings. Originally it would not work at all (always got the 404). Now sometimes the 404 appears, and sometimes I get the country/language select page, and then it works.
I have Firefox installed for when I get these kind of websites. Knowing SAA it would be pointless to report it to them but you could try.
Getting very frustrated now, I am only having this problem on the one machine. Nothing clears the problem.
I have cleared cache and cookies. all settings checked and they are identical to my Mac.
Called SAA, no answer( think they did not know much about anything).