diff --git a/ffi-tools/ffi-tools.c b/ffi-tools/ffi-tools.c
index 6b5396e..83b26b9 100644
--- a/ffi-tools/ffi-tools.c
+++ b/ffi-tools/ffi-tools.c
@@ -21,7 +21,7 @@ int length_scheme_list(s48_value list)
   
   S48_GC_PROTECT_2(list, res);
   FFIT_CHECK_LIST(list);
-  res = s48_call_scheme(scheme_list_length_function, 1, list);
+  res = s48_call_scheme(S48_SHARED_BINDING_REF(scheme_list_length_function), 1, list);
   S48_GC_UNPROTECT();
   return s48_extract_integer(res);
 }
@@ -32,7 +32,7 @@ int call_scheme_boolean_p(s48_value v)
   S48_DECLARE_GC_PROTECT(2);
   
   S48_GC_PROTECT_2(v, res);
-  res = s48_call_scheme(scheme_boolean_p_function, 1, v);
+  res = s48_call_scheme(S48_SHARED_BINDING_REF(scheme_boolean_p_function), 1, v);
   S48_GC_UNPROTECT();
   return S48_TRUE_P(res);
 }
@@ -43,7 +43,7 @@ int call_scheme_integer_p(s48_value v)
   S48_DECLARE_GC_PROTECT(2);
   
   S48_GC_PROTECT_2(v, res);
-  res = s48_call_scheme(scheme_integer_p_function, 1, v);
+  res = s48_call_scheme(S48_SHARED_BINDING_REF(scheme_integer_p_function), 1, v);
   S48_GC_UNPROTECT();
   return S48_TRUE_P(res);
 }
@@ -92,5 +92,6 @@ void ffit_init_hook(void)
 
   scheme_list_length_function = s48_get_imported_binding("length");
   scheme_integer_p_function = s48_get_imported_binding("integer?");
-  scheme_boolean_p_function = s48_get_imported_binding("boolean?");
+  scheme_boolean_p_function = s48_get_imported_binding("boolean?"); 
 }
+