diff --git a/ldebug.h b/ldebug.h
index 6e1dfd28..7fba153c 100644
--- a/ldebug.h
+++ b/ldebug.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.h,v 2.10 2013/05/06 17:19:11 roberto Exp roberto $
+** $Id: ldebug.h,v 2.11 2014/02/25 14:31:16 roberto Exp roberto $
 ** Auxiliary functions from Debug Interface module
 ** See Copyright Notice in lua.h
 */
@@ -25,8 +25,9 @@ LUAI_FUNC l_noret luaG_typeerror (lua_State *L, const TValue *o,
                                                 const char *opname);
 LUAI_FUNC l_noret luaG_concaterror (lua_State *L, const TValue *p1,
                                                   const TValue *p2);
-LUAI_FUNC l_noret luaG_aritherror (lua_State *L, const TValue *p1,
-                                                 const TValue *p2);
+LUAI_FUNC l_noret luaG_opinterror (lua_State *L, const TValue *p1,
+                                                 const TValue *p2,
+                                                 const char *msg);
 LUAI_FUNC l_noret luaG_tointerror (lua_State *L, const TValue *p1,
                                                  const TValue *p2);
 LUAI_FUNC l_noret luaG_ordererror (lua_State *L, const TValue *p1,
diff --git a/ltm.c b/ltm.c
index 94c077d5..f4625627 100644
--- a/ltm.c
+++ b/ltm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltm.c,v 2.29 2014/07/18 13:36:14 roberto Exp roberto $
+** $Id: ltm.c,v 2.30 2014/11/02 19:19:04 roberto Exp roberto $
 ** Tag methods
 ** See Copyright Notice in lua.h
 */
@@ -122,10 +122,12 @@ void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2,
         lua_Number dummy;
         if (tonumber(p1, &dummy) && tonumber(p2, &dummy))
           luaG_tointerror(L, p1, p2);
+        else if (event != TM_IDIV)
+          luaG_opinterror(L, p1, p2, "perform bitwise operation on");
         /* else go through */
       }
       default:
-        luaG_aritherror(L, p1, p2);
+        luaG_opinterror(L, p1, p2, "perform arithmetic on");
     }
   }
 }