diff --git a/src/c/interpreter.d b/src/c/interpreter.d
index 67c860bad..eaae2b4c3 100644
--- a/src/c/interpreter.d
+++ b/src/c/interpreter.d
@@ -24,85 +24,73 @@
 static void
 VEbad_lambda_too_many_args(cl_object bytecodes, cl_object frame)
 {
-  FEprogram_error("Too many arguments passed to "
-                  "function ~A~&Argument list: ~S",
-                  2, bytecodes, cl_apply(2, @'list', frame));
+  ecl_ferror(ECL_EX_VM_BADARG_EXCD, bytecodes, frame);
 }
 
 static void
 VEbad_lambda_unknown_keyword(cl_object bytecodes, cl_object frame)
 {
-  FEprogram_error("Unknown keyword argument passed to function ~S.~&"
-                  "Argument list: ~S", 2, bytecodes,
-                  cl_apply(2, @'list', frame));
+  ecl_ferror(ECL_EX_VM_BADARG_UNKK, bytecodes, frame);
 }
 
 static void
 VEbad_lambda_odd_keys(cl_object bytecodes, cl_object frame)
 {
-  FEprogram_error("Function ~A called with odd number "
-                  "of keyword arguments.",
-                  1, bytecodes);
+  ecl_ferror(ECL_EX_VM_BADARG_ODDK, bytecodes, frame);
 }
 
 static void
 VEwrong_arg_type_endp(cl_object reg0)
 {
-  FEwrong_type_only_arg(@[endp], reg0, @[list]);
+  ecl_ferror(ECL_EX_VM_BADARG_ENDP, ECL_NIL, reg0);
 }
 
 static void
 VEwrong_arg_type_car(cl_object reg0)
 {
-  FEwrong_type_only_arg(@[car], reg0, @[cons]);
+  ecl_ferror(ECL_EX_VM_BADARG_CAR, ECL_NIL, reg0);
 }
 
 static void
 VEwrong_arg_type_cdr(cl_object reg0)
 {
-  FEwrong_type_only_arg(@[cdr], reg0, @[cons]);
+  ecl_ferror(ECL_EX_VM_BADARG_CDR, ECL_NIL, reg0);
 }
 
 static void
-VEwrong_arg_type_nth_val(cl_fixnum n)
+VEwrong_arg_type_nth_val()
 {
-  FEerror("Wrong index passed to NTH-VAL", 1, ecl_make_fixnum(n));
+  ecl_ferror(ECL_EX_VM_BADARG_NTH_VAL, ECL_NIL, ECL_NIL);
 }
 
 static void
 VEassignment_to_constant(cl_object var)
 {
-  FEassignment_to_constant(var);
+  ecl_ferror(ECL_EX_V_CSETQ, var, ECL_NIL);
 }
 
 static void
 VEunbound_variable(cl_object var)
 {
-  FEunbound_variable(var);
+  ecl_ferror(ECL_EX_V_UNBND, var, ECL_NIL);
 }
 
 static void
-VEwrong_num_arguments(cl_object fname)
+VEwrong_num_arguments(cl_object fun)
 {
-  FEwrong_num_arguments(fname);
+  ecl_ferror(ECL_EX_F_NARGS, fun, ECL_NIL);
 }
 
 static void
 VEundefined_function(cl_object fun)
 {
-  FEundefined_function(fun);
+  ecl_ferror(ECL_EX_F_UNDEF, fun, ECL_NIL);
 }
 
 static void
 VEinvalid_function(cl_object fun)
 {
-  FEinvalid_function(fun);
-}
-
-static void
-VEclose_around_arg_type()
-{
-  FEerror("Internal error: ecl_close_around should be called on t_bytecodes or t_bclosure.", 0);
+  ecl_ferror(ECL_EX_F_INVAL, fun, ECL_NIL);
 }
 
 /* ------------------------------ LEXICAL ENV. ------------------------------ */
@@ -248,7 +236,7 @@ static cl_object
 close_around_self(cl_object fun) {
   cl_object v, template;
   if(ecl_t_of(fun) != t_bytecodes)
-    VEclose_around_arg_type();
+    VEinvalid_function(fun);
   template = fun->bytecodes.flex;
   if(Null(template)) return fun;
   /* Make a closure */
@@ -286,7 +274,7 @@ close_around_self_fixup(cl_object fun, cl_object lcl_env, cl_object lex_env) {
     fun->bclosure.lex = new_lex;
     break;
   default:
-    VEclose_around_arg_type();
+    VEinvalid_function(fun);
   }
 }
 
@@ -296,7 +284,7 @@ ecl_close_around(cl_object fun, cl_object lcl_env, cl_object lex_env) {
   cl_object v, new_lex, template, entry;
   cl_fixnum nlex, idx, ndx;
   if(ecl_t_of(fun) != t_bytecodes)
-    VEclose_around_arg_type();
+    VEinvalid_function(fun);
   template = fun->bytecodes.flex;
   if(Null(template)) return fun;
   /* Close around */
@@ -1241,7 +1229,7 @@ ecl_interpret(cl_object frame, cl_object closure, cl_object bytecodes)
     CASE(OP_NTHVAL); {
       cl_fixnum n = ecl_fixnum(ECL_STACK_POP_UNSAFE(the_env));
       if (ecl_unlikely(n < 0)) {
-        VEwrong_arg_type_nth_val(n);
+        VEwrong_arg_type_nth_val();
       } else if ((cl_index)n >= the_env->nvalues) {
         reg0 = ECL_NIL;
       } else if (n) {