Win32 Listview Grouping Problems

[NanoBytes]

I am having problems using groupings in my listview control. The code is not compiling, it says that the LVGROUP structure has not been declaired, and various other grouping issues. Because the program isint even compileing I assume that i am not includeing some nessesary file or something, I have already set WINVER to 0x0501 which allows for the nessesary defnitions. I am using windows XP black, on code blocks mingw. I am at a loss as to how to fix this problem and any help at all would be apriciated, thanks everybody :)