How to display text with the GUI Text object when using the Ultimate FPS Camera Asset

In my FPS game, I have a GUI Text object in the hierarchy which displays text to the player. It is controlled by a C# script (TextDisplay.cs) that creates and instance using ManualSingleton.Instance. In order to show text on the HUD, any object in the the scene can call TextDisplay.ShowMessage("text message"). It works fine when using the FPS camera in Unity's standard assets, but not with the Ultimate FPS Camera asset I just purchased. I've already used Debug.Log() to confirm that the TextDisplay class is supposed to be showing the text on the HUD. Has anyone used the Ultimate FPS Camera asset before? Any help would be appreciated.

Thanks, Marvin