Added alternative exception handling for nogui implementation

[Synirrr]

Small change to how exceptions are handled when no-gui is selected.

[Synirrr]

Rationale for the change is that when no gui is set users would expect any UI elements to not be rendered during any aspect of the application running. So having a message box pop up that hangs the process unless a user selects "Okay" seems counterintuitive to the no gui setting.