Message Box

[jalkadir gosonic ca]

OS: MSW-XP
GTK+: 2.0.X

Hi!
In my application there are several buttons that are no active, yet. What
I would like to do is

to display "Info" Dialog Box when the user selects one of the inactive
Buttos.
I do this I have witten a function that goes like this:

void Message(){
GtkWidget* label, dialog;
dialog = gtk_message_dialog_new(
 (GTK_WINDOW(TopWidget),         //Parent
 GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT, //Flags
 GTK_MESSAGE_INFO,              // Icon
 GTK_BUTTONS_OK,                // Button label
 Under construction");          // Message
}

But this gives me an error that says:
main.hpp:27: error: no match for 'operator=' in 'dialog =
gtk_message_dialog_new(0u,

(GtkDialogFlags)3u, GTK_MESSAGE_INFO,  GTK_BUTTONS_OK, ((const
char*)"Under construction"))'
C:/Dev-Cpp/include/gtk-2.0/gtk/gtkwidget.h:164: note: candidates are:
_GtkWidget&

_GtkWidget::operator=(const _GtkWidget&)make.exe: *** [main.o] Error
1Execution terminated

What am I doing wrong?!! anybody?
Thanks