There is no need to include *_W2K functons in VisualStyles.bas module as those will be used only when "GetComCtlVersion >= 6".
And this is not the case in W2K. That's why there will be no subclassing applied.
Your program crashes on Win2k currently (checked on Win 2k Server SP4 Rollup 2). I added aliases #410/412/413, and it works fine now. I didn't dig deeply to know how and where your subclassing is initiated.
But I know that aliases solved problem for me.