diff --git a/src/gsi/gsi/gsiCallback.h b/src/gsi/gsi/gsiCallback.h
index e3903cd5a..e37621823 100644
--- a/src/gsi/gsi/gsiCallback.h
+++ b/src/gsi/gsi/gsiCallback.h
@@ -41,6 +41,7 @@ struct GSI_PUBLIC Callee
   virtual ~Callee () { }
 
   virtual void call (int id, SerialArgs &args, SerialArgs &ret) const = 0;
+  virtual bool can_call () const { return true; }
 };
 
 /**
@@ -72,7 +73,7 @@ struct Callback
 
   bool can_issue () const
   {
-    return callee.get () != 0;
+    return callee && callee->can_call ();
   } 
 
 // 0 arguments
diff --git a/src/pya/pya/pyaObject.cc b/src/pya/pya/pyaObject.cc
index 938e40488..2c3120418 100644
--- a/src/pya/pya/pyaObject.cc
+++ b/src/pya/pya/pyaObject.cc
@@ -111,6 +111,50 @@ bool CallbackFunction::operator== (const CallbackFunction &other) const
   return callable_ref () == other.callable_ref ();
 }
 
+/**
+ *  @brief An adaptor class for the callback mechanism
+ */
+class Callee
+  : public gsi::Callee
+{
+public:
+  /**
+   *  @brief Constructor for a Callee object pointing the to given Python object
+   */
+  Callee (PYAObjectBase *obj);
+
+  /**
+   *  @brief Destructor
+   */
+  ~Callee ();
+
+  /**
+   *  @brief Adds a callback (given by the CallbackFunction)
+   *  This method returns a callback ID which can be used to register the callback
+   *  at an GSI object.
+   */
+  int add_callback (const CallbackFunction &vf);
+
+  /**
+   *  @brief Clears all callbacks registered
+   */
+  void clear_callbacks ();
+
+  /**
+   *  @brief Implementation of the Callee interface
+   */
+  virtual void call (int id, gsi::SerialArgs &args, gsi::SerialArgs &ret) const;
+
+  /**
+   *  @brief Implementation of the Callee interface
+   */
+  virtual bool can_call () const;
+
+private:
+  PYAObjectBase *mp_obj;
+  std::vector<CallbackFunction> m_cbfuncs;
+};
+
 // --------------------------------------------------------------------------
 //  Implementation of Callee
 
@@ -138,6 +182,12 @@ Callee::clear_callbacks ()
   m_cbfuncs.clear ();
 }
 
+bool
+Callee::can_call () const
+{
+  return pya::PythonInterpreter::instance () != 0;
+}
+
 void 
 Callee::call (int id, gsi::SerialArgs &args, gsi::SerialArgs &ret) const
 {
diff --git a/src/rba/rba/rba.cc b/src/rba/rba/rba.cc
index 75ccdab25..4705f2aed 100644
--- a/src/rba/rba/rba.cc
+++ b/src/rba/rba/rba.cc
@@ -1732,8 +1732,7 @@ RubyInterpreter::~RubyInterpreter ()
 
   rb_release_top_self ();
 
-  //  This prevents reinitialization
-  sp_rba_interpreter = reinterpret_cast<RubyInterpreter *> (1);
+  sp_rba_interpreter = 0;
 }
 
 RubyInterpreter *RubyInterpreter::instance ()
diff --git a/src/rba/rba/rbaInspector.cc b/src/rba/rba/rbaInspector.cc
index 26ffa7aab..70a7c9865 100644
--- a/src/rba/rba/rbaInspector.cc
+++ b/src/rba/rba/rbaInspector.cc
@@ -132,7 +132,7 @@ public:
     : m_hash (hash)
   {
     rb_gc_register_address (&m_hash);
-    m_keys = rb_ary_new2 (RHASH_SIZE (m_hash));
+    m_keys = rb_ary_new2 (long (RHASH_SIZE (m_hash)));
     rb_gc_register_address (&m_keys);
     rb_hash_foreach (m_hash, (int (*)(...)) &push_key_to_ary_i, m_keys);
   }
diff --git a/src/rba/rba/rbaInternal.cc b/src/rba/rba/rbaInternal.cc
index e92dde690..80836da77 100644
--- a/src/rba/rba/rbaInternal.cc
+++ b/src/rba/rba/rbaInternal.cc
@@ -301,6 +301,11 @@ Proxy::signal_handler (const gsi::MethodBase *meth)
   return sh;
 }
 
+bool Proxy::can_call () const
+{
+  return rba::RubyInterpreter::instance () != 0;
+}
+
 void
 Proxy::call (int id, gsi::SerialArgs &args, gsi::SerialArgs &ret) const
 {
diff --git a/src/rba/rba/rbaInternal.h b/src/rba/rba/rbaInternal.h
index 4957e5881..cca746f6d 100644
--- a/src/rba/rba/rbaInternal.h
+++ b/src/rba/rba/rbaInternal.h
@@ -147,6 +147,7 @@ public:
   VALUE signal_handler (const gsi::MethodBase *meth);
 
   virtual void call (int id, gsi::SerialArgs &args, gsi::SerialArgs &ret) const;
+  virtual bool can_call () const;
 
 private:
   const gsi::ClassBase *m_cls_decl;
diff --git a/src/rbastub/rba.cc b/src/rbastub/rba.cc
index 71718be2b..cf12dd57a 100644
--- a/src/rbastub/rba.cc
+++ b/src/rbastub/rba.cc
@@ -40,8 +40,7 @@ RubyInterpreter::RubyInterpreter ()
 
 RubyInterpreter::~RubyInterpreter ()
 {
-  //  This prevents reinitialization
-  sp_rba_interpreter = reinterpret_cast<RubyInterpreter *> (1);
+  sp_rba_interpreter = 0;
 }
 
 RubyInterpreter *RubyInterpreter::instance ()