Ok. I have sorted it out, kind of. The program starts but everything is upside down. What's going on there? Is there anything wrong with the script?

#include <acknex.h>
#include <default.c>

PANEL* first_pan =
{
BMAP = "panel.tga";
pos_x = 200;
pos_y = 250;
button (100,100,"clicked.tga","normal.tga","over.tga",NULL,NULL,NULL);
flags = OVERLAY | SHOW;
}
function main ()
{
screen_size.x = 600;
screen_size.y = 600;
screen_color.green = 170;
}

And also the button doesn't change when I click it or move the mouse over it.