diff --git a/compiler/global/idents.ml b/compiler/global/idents.ml
index 6899488..a946fb3 100644
--- a/compiler/global/idents.ml
+++ b/compiler/global/idents.ml
@@ -123,10 +123,22 @@ struct
 
   (** This function should be called every time we enter a node *)
   let enter_node n =
+    (* TODO : see copy_node; same problem *)
     (if not (QualEnv.mem n !node_env)
     then node_env := QualEnv.add n (ref NamesSet.empty) !node_env);
     used_names := QualEnv.find n !node_env
 
+  (** Copy environment of node of name [n] to new node name [n'] *)
+  let copy_node n n' =
+    (* TODO : do something smarter than create empty used names set *)
+    (* this happen when an object file is loaded: the used names set
+       of loaded nodes is not properly set *)
+    if not (QualEnv.mem n !node_env)
+    then node_env := QualEnv.add n (ref NamesSet.empty) !node_env;
+    assert (not (QualEnv.mem n' !node_env));
+    let used_names = !(QualEnv.find n !node_env) in
+    node_env := QualEnv.add n' (ref used_names) !node_env
+
   (** @return a unique string for each identifier. Idents corresponding
       to variables defined in the source file have the same name unless
       there is a collision. *)
@@ -172,5 +184,6 @@ let ident_of_name ?(reset=false) s =
 let source_name id = id.source
 let name id = UniqueNames.name id
 let enter_node n = UniqueNames.enter_node n
+let copy_node = UniqueNames.copy_node
 
 let print_ident ff id = Format.fprintf ff "%s" (name id)
diff --git a/compiler/global/idents.mli b/compiler/global/idents.mli
index 01eab6a..8d37f14 100644
--- a/compiler/global/idents.mli
+++ b/compiler/global/idents.mli
@@ -67,6 +67,8 @@ val is_reset : ident -> bool
 (** /!\ [enter_node qualname] should be called every time we enter a node with name [qualname]. *)
 val enter_node : Names.qualname -> unit
 
+val copy_node : Names.qualname -> Names.qualname -> unit
+
 (** Maps taking an identifier as a key. *)
 module Env :
 sig
diff --git a/compiler/main/mls2seq.ml b/compiler/main/mls2seq.ml
index 9e08f24..91ed228 100644
--- a/compiler/main/mls2seq.ml
+++ b/compiler/main/mls2seq.ml
@@ -60,7 +60,7 @@ let mk_target ?(interface=IMinils ignore) ?(load_conf = no_conf) name pt =
 
 (** Writes a .epo file for program [p]. *)
 let write_object_file p =
-  let filename = (Names.modul_to_string p.Minils.p_modname)^".epo" in
+  let filename = (String.uncapitalize (Names.modul_to_string p.Minils.p_modname)) ^".epo" in
   let epoc = open_out_bin filename in
     output_value epoc p;
     close_out epoc;
diff --git a/compiler/minils/transformations/callgraph.ml b/compiler/minils/transformations/callgraph.ml
index cf6cf39..30eb751 100644
--- a/compiler/minils/transformations/callgraph.ml
+++ b/compiler/minils/transformations/callgraph.ml
@@ -27,6 +27,7 @@
 (*                                                                     *)
 (***********************************************************************)
 open Names
+open Idents
 open Types
 open Misc
 open Location
@@ -129,6 +130,7 @@ struct
             "_params_" params in
         let new_ln =
           Modules.fresh_value_in "callgraph" (n^param_string^"_") q in
+        Idents.copy_node ln new_ln;
         nodes_names := M.add (ln, params) new_ln !nodes_names
 
   (** Adds an instance of a node. *)
diff --git a/compiler/obc/c/cgen.ml b/compiler/obc/c/cgen.ml
index 1b2ff53..bc3cf30 100644
--- a/compiler/obc/c/cgen.ml
+++ b/compiler/obc/c/cgen.ml
@@ -752,6 +752,7 @@ let cdefs_and_cdecls_of_class_def cd =
   (** We keep the state of our class in a structure, holding both internal
       variables and the state of other nodes. For a class named ["cname"], the
       structure will be called ["cname_mem"]. *)
+  Idents.enter_node cd.cd_name;
   let step_m = find_step_method cd in
   let memory_struct_decl = mem_decl_of_class_def cd in
   let out_struct_decl = out_decl_of_class_def cd in
diff --git a/compiler/obc/c/cmain.ml b/compiler/obc/c/cmain.ml
index b2105d7..66f28e6 100644
--- a/compiler/obc/c/cmain.ml
+++ b/compiler/obc/c/cmain.ml
@@ -364,12 +364,17 @@ let mk_main name p =
       let classes = program_classes p in
       let n_names = !Compiler_options.assert_nodes in
       let find_class n =
-        try List.find (fun cd -> cd.cd_name.name = n) classes
-        with Not_found ->
-          Format.eprintf "Unknown node %s.@." n;
-          exit 1 in
+        List.find (fun cd -> cd.cd_name.name = n) classes
+      in
 
-      let a_classes = List.map find_class n_names in
+      let a_classes =
+        List.fold_left
+          (fun acc n ->
+             try
+               find_class n :: acc
+             with Not_found -> acc)
+          []
+          n_names in
 
       let (var_l, res_l, step_l) =
         let add cd (var_l, res_l, step_l) =
@@ -378,10 +383,12 @@ let mk_main name p =
         List.fold_right add a_classes ([], [], []) in
 
       let n = !Compiler_options.simulation_node in
-      let (mem, nvar_l, res, nstep_l) = main_def_of_class_def (find_class n) in
-      let defs = match mem with None -> [] | Some m -> [m] in
-      let (var_l, res_l, step_l) =
-        (nvar_l @ var_l, res @ res_l, nstep_l @ step_l) in
+      let (defs, var_l, res_l, step_l) =
+        try
+          let (mem, nvar_l, res, nstep_l) = main_def_of_class_def (find_class n) in
+          let defs = match mem with None -> [] | Some m -> [m] in
+          (defs, nvar_l @ var_l, res @ res_l, nstep_l @ step_l)
+        with Not_found -> ([],var_l,res_l,step_l) in
 
       [("_main.c", Csource (defs @ [main_skel var_l res_l step_l]));
        ("_main.h", Cheader ([name], []))];