A syntax error was found in a DO or LOOP instruction. You probably used BY, TO, FOR, WHILE, or UNTIL twice, used a WHILE and an UNTIL, or used BY, TO, or FOR when there is no control variable specified.
The associated subcodes are:
001
Only one WHILE or UNTIL condition can be used on the same loop.
901
Incorrect data following FOREVER keyword on the loop; found "data".
902
DO or LOOP keyword keyword can be specified only once.
903
No INDEX or ITEM control variable specified on a WITH loop.
904
OVER keyword expected for a WITH loop.
905
COUNTER keyword not allowed on a simple DO instruction.
