15.64.22  ERRORS 

SET ERRORS [{DEFERRED|IMMEDIATE|LIST}] [WAIT|PAUSE[=ON|OFF]]

     1.  DEFERRED - The error messages appear after the plot is finished.
     2.  IMMEDIATE  -  The  error  messages  appear  when  the  command is
         entered.
     3.  LIST - The error messages appear only in the listing file.
     4.  WAIT  -  When error messages are immediate, WAIT causes TOPDRAWER
         to wait after each message.  PAUSE is a synonym for wait.

This option remains the same until changed by a SET ERRORS command.
(Default:IMMEDIATE,NOWAIT)