Isometric Mouse position to Tile

Reading the other topic: http://www.java-gaming.org/index.php/topic,21914.0.html
The answer seems to be:
http://www.bookofhook.com/Images/Isometric_Images/screen_to_map.gif
from: http://trac.bookofhook.com/bookofhook/trac.cgi/wiki/OverviewOfIsometricEngineDevelopment

But I can’t get mine to work.
I’m working with the code from Killer Game Programming in Java: http://fivedots.coe.psu.ac.th/~ad/jg/ch064/index.html
I’m suspecting it’s because his tiles are mapped differently? Or maybe the solution is for c++, and java’s coordinates start at top-left instead of bot-left?

On a side note: Is Killer’s code a good place to start for isometric games? Anyone know better sourcecode? I’m trying to make something like: http://www.poxnora.com/index.do
There doesn’t seem to be any decent iso tut/sourcecode (that’s not c++) googling.

Edit: I’m not getting any replies. I see a lot of people mention Killer on the net. So surely SOMEONE must have a mouse iso working for it and can help me out.

Anyways here’s my code for that section:

int w = world.tileWidth; int h = world.tileHeight;
int sx = e.getX() - 12; int sy = e.getY() - 8;
int x = ( w*sy + h*sx )/( w*h );
int y = ( w*sy - h*sx )/( w*h );
System.out.println(x + " " + y);
player.move( x, y );