Library /sys$common/syshlp/basichelp.hlb Run time errors, ON_STAOUT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ON statement out of range (ERR=58)

  The index value in an ON GOTO or ON GOSUB statement is less than 1  or
  greater  than  the  number of line numbers in the list.  Check program
  logic to make sure that the index value is greater than  or  equal  to
  one,  and  less  than or equal to the number of line numbers in the ON
  GOTO or ON GOSUB statement.