OS X :: Certain Websites Won't Open?

I've recently been having some trouble accessing certain websites from my macbook.

What happens is that once I enter the address for the particular website in my address bar and press return/ enter, the browser attempts to load the website, but cannot seem to do so, as if it is being blocked in some way. After a minute or so of trying, I usually get the message 'Page Load Error' accompanied by 'Network Timeout' or 'Failed to open page' in Safari. Changing browser does not seem to work (same results with Camino, FF, Safari, and Opera), and using VMWare Fusion running XP, I get the same thing.

My setup is white C2D macbook, connecting wirelessly to an AEBS. I have another desktop, and 3 other laptops, as well as an iPod Touch and PS3 on the network and all of these can access the sites as normal. Just to let people know, I also changed to OpenDNS and flushed the DNS cache.

Could anyone shed some light on why this is happening? Alternatively anything else I should be looking to do (besides reinstall of OSX)?