Alright, this is my problem. (i'm using Borland C++ builder 6,windows XP)

I have decleared my variables globaly.
I have made a function that is passed a class and a TImage(both are global).

It compiles, BUT when i click the button, it nukes.

Here is the function code
Code:
void move_ship_left(Ship_1 *U_Ship, TImage *U_sprite)
{
int x1;
int y1;

//adds to the x,y values
x1 = (U_Ship->x1) - 5;
y1 = (U_Ship->y1) + 0;

//sets up new x,y values
U_Ship->x1 =x1;
U_Ship->y1 =y1;
Form1->Repaint();
Form1->Canvas->Draw(x1,y1,U_sprite->Picture->Graphic ) ;

}
Here is the function call

Code:
 move_ship_left(User_Ship,Ship_sprite);
here is the variable that's declared globally in another .h file
Code:
extern        Ship_1 *User_Ship;
extern        TImage *Ship_sprite;
Please help me! This is due for a project, and I NEED to fix it!

thx for the help