diff --git a/src/vm/fzl_vm_extern.c b/src/vm/fzl_vm_extern.c
index 52f8fdf..7cefb9b 100644
--- a/src/vm/fzl_vm_extern.c
+++ b/src/vm/fzl_vm_extern.c
@@ -188,7 +188,7 @@ fzl_vm_extern_t *fzl_vm_init_externs(fzl_vm_reader_t *reader)
       return NULL;
     }
 
-    if (!prepare_sym(reader, sym, fn, &ex->syms[i]))
+    if (!prepare_sym(reader, sym, fn, &ex->syms[ex->syms_loaded++]))
     {
       if (!ex_err[0])
       {