Well, it doesn't look that bad, although you might want to use some different things to find the objects on the screen such as DTMs or TPAs. One thing I see it that after you BuyFood you never close the window so how is it supposed to find the bank booth??? :p So all you need to do is add CloseWindow;
Procedure BuyFood;
var x, y: integer;
begin
if findObj(x,y, 'hoco', 1452102, 5)then
begin
mouse(x, y, 2, 1, false);
chooseoption('all') ;
end;
CloseWindow;
end;
Also, the reason it probably isnt opening the shop is because the color you have chosen isn't good enough because every time you log in/out the colors change on runescape. You can use ACA(Auto Color Aid) which you can find somewhere around the forums.
This thread was very helpful to me when I started scripting, might want to bookmark it.