iPhone 4 - Do I have a stripped screw?

Hello, i was about 5 % in to replacing the display of my iPhone 4 screen and i got to step 8 (the tutorial on this website) and i had some problems with the screw on the right, the Phillips screw driver i was using worked on every other Phillips screw on the phone.

This is the screw: http://i.imgur.com/lPXkn4P.jpg

Is it stripped? How do i undo it? I tried with a rubber band it did not work:( i bought this phone second hand just to let you know.

Thanks.

PS. IF i need to get another screw driver, where in the UK could i buy one from (not online)/.