Error Displaying only Message Code and not Message Text

Function used to call Error Messages in Oracle Self Service via User Hook

hr_utility.set_message (800, 'XXX_HR_LEAVE_OVERLAP');

hr_utility.raise_error;

Run the Following Request & Bounce Apache (Bounce only if Message Text doesn't Appear after running the Request)

Navigation: System Administrator à View à Request à Submit New Request

Request Name: Generate Messages