E0006: a block whose END keyword never comes

PROGRAM ends with END_PROGRAM, VAR with END_VAR, IF with END_IF, and so on. The file ended, or another block’s end came first, before this one was closed. The error points at the block’s start.

PROGRAM main
VAR x : INT; END_VAR
x := x + 1;
(* E0006: PROGRAM main is not closed, END_PROGRAM missing *)