Okay i guess it a problem to do with my NAV version....... I'm currently using NAV 2009 R2, Just on curiosity i tried opening the database with NAV 2009 SP1 and it worked just like charm. I wonder what limitation is paused with one version compared to the other.
In addition, after opening my database with SP1 and providing authentication, as it was loading i had to press F12 which by default brings up the Main Menu, then select the company and swooosh...... good to go!!