I declared a COM class best I can from looking at other COM class but I am getting syntax errors. I could not find any guide/manual on COM development.
If you mean general COM manual, the nicest introduction I found about it is this URL 'http://www.microsoft.com/Com/news/drgui.asp'.
If it's the Wine part of COM, François's answer is to be read :-)
Out of curiosity, on what are you working on ?
Lionel