Display an error message on the screen and wait for response
──────────────────────────────────────────────────────────────────────────────

 Syntax

        GT_Error([<cMessage>]) -> lSuccess

 Arguments:

      <cMessage> is a charater string todisplay.

 Returns:

      lSuccess

 Description:

      To display an error message on the screen, wait for
      the user to respond and remove the message.

 Examples:

      IF .NOT. lSuccess
          GT_Error("It didn't Work !")
      ENDIF

 Source: GT_ERROR.PRG

 Author:  Martin Bryant