diff --git a/blk/043 b/blk/043
index e4c6099..60f3f7c 100644
--- a/blk/043
+++ b/blk/043
@@ -12,4 +12,5 @@ have to consume it to avoid PSP leak.
 ]         --   End interpretative mode.
 ABORT     --   Resets PS and RS and returns to interpreter.
 ABORT" x" --   *I* Compiles a ." followed by a ABORT.
-EXECUTE   a -- Execute wordref at addr a
+ERR       a -- Prints a and ABORT. Defined early and used by
+               drivers.                                 (cont.)
diff --git a/blk/044 b/blk/044
index f15cb2f..ae2cdc6 100644
--- a/blk/044
+++ b/blk/044
@@ -1,3 +1,4 @@
+EXECUTE   a -- Execute wordref at addr a
 INTERPRET --   Get a line from stdin, compile it in tmp memory,
                then execute the compiled contents.
 LEAVE     --   In a DO..LOOP, exit at the next LOOP call.
diff --git a/blk/394 b/blk/394
index 6fb571f..d6742b5 100644
--- a/blk/394
+++ b/blk/394
@@ -1,4 +1,5 @@
 : ABORT (resSP) QUIT ;
+: ERR LIT< (print) (find) IF EXECUTE THEN ABORT ;
 : = CMP NOT ; : < CMP -1 = ; : > CMP 1 = ;
 : 0< 32767 > ; : >= < NOT ; : <= > NOT ; : 0>= 0< NOT ;
 ( n l h -- f )
diff --git a/blk/421 b/blk/421
index f73d4ed..3c7e85b 100644
--- a/blk/421
+++ b/blk/421
@@ -12,5 +12,5 @@
 : CRLF CR LF ; : SPC 32 EMIT ;
 : NL 0x0a RAM+ @ ( NLPTR ) DUP IF EXECUTE ELSE DROP CRLF THEN ;
 : (ok) SPC LIT" ok" (print) NL ;
-: (uflw) LIT" stack underflow" (print) ABORT ;
-: (wnf) (print) SPC LIT" word not found" (print) ABORT ;
+: (uflw) LIT" stack underflow" ERR ;
+: (wnf) (print) SPC LIT" word not found" ERR ;
diff --git a/emul/forth.bin b/emul/forth.bin
index 1f56f0a..d88b416 100644
Binary files a/emul/forth.bin and b/emul/forth.bin differ