First of all check the MBL user interface Settings > Remote access and see exactly what Conectivity Status is displaying. (see the printscreen here: http://www.flickr.com/photos/29878505@N04/6250886518/ ).
If it says “Failed” then it seems you have the same problem as I do: I can’t access MBL using WD2go, WDphotos, also can’t register an email for Remote Web Access.
WD Support suggested a factory restore. I didn’t do that because I don’t have where to move all my data stored.
But I found here on forum a similar story told by user mudkip ( http://community.wdc.com/t5/My-Book-Live/Remote-Access-displayed-as-quot-Failed-quot/m-p/259838#M4383 )
He performed a factory restore, MBL worked fine for a couple of days then again MBL failed to connect to the internet.
Well, first of all check the MBL’s conectivity status!