Does anyone know how to stop the standard Visual Error message from being displayed when an error occurs within an error routine?

I have a Class that has several methods to handle error handling, which works fine in most error situations. It is called like this:

PUBLIC App_Name
App_Name = CREATEOBJECT("CisApp")
IF TYPE('App_Name') = "O"
ON ERROR App_Name.Disp_Err(Error(),Message(),Message(1),Prog(),Lineno(),SYS(16),.T.)
ENDIF

The problem occurs when inside one of my methods, I attempt to store the users name who has the error. If the Users table is opened exclusive somewhere else, when I attempt to open it, I get the standard windows error message, which I don't want the users to have displayed.

I have tried to do another on error statement within my error method, to display a error message using my screens which works, but it fires after the windows message has been displayed.

Any ideas?