It's the OnPut function in edittime.cpp, though I agree that it's not really an ideal way to give information.
Sorry if I confused you. This messagebox is not going to be in the released version of the plugin. This is just so that I can get more familiar with the Plugin SDK, and my friend wants a specific plugin that does this.
By the way, this may sound dumb, but what would the code look like for the Message Box Popup? I keep getting errors.
Thanks for all of the help, guys!