After i made some changes to my dialog.. it show me this error with this line

enum { IDD = IDD_CIBUTTON_DIALOG };

error:
error C2065: 'IDD_CIBUTTON_DIALOG' : undeclared identifier
error C2057: expected constant expression
I made add an onclick event to my button in the dialog and there comes the error ;( ... any idea where has gone wrong?

Thanks.