No need to be amazed at all! I found the answer to my problem. Anyway, for your information, it will work in Win 2000 without any problem because the uxtheme P/Invoke function was "just declared" in the code and "was never actually used" or "called" and hence there is no issue for it to be running properly in Win 2000.

Check this link out http://www.dotnet247.com/247reference/msgs/30/150431.aspx I'm not an expert yet, but I play one at work. Yeah and here too.