Tile based scroller?

Hey everyone.

I have been trying for hours on end to solve this whole problem (probably very simple, just needing an outside view).

I have done this tutorial as a basic test for the scrolling system http://www.kirupa.com/developer/actionscript/rpgprogramming6.htm

I have successfully managed to make the background scroll (Was the easy part).
The hard part is having the center of the screen on the character in the correct position on the map.

The map is 1920 x 1920 with a grid size of 64. Thats a 30 x 30 grid.
The movie size is 500 x 500.

Any help is greatly appreciated!