diff --git a/src/dbus_support.py b/src/common/dbus_support.py
similarity index 86%
rename from src/dbus_support.py
rename to src/common/dbus_support.py
index d4f7542a3..f4b997587 100644
--- a/src/dbus_support.py
+++ b/src/common/dbus_support.py
@@ -21,6 +21,8 @@ import sys
 from common import gajim
 from common import exceptions
 
+_GAJIM_ERROR_IFACE = 'org.gajim.dbus.Error'
+
 try:
 	import dbus
 	import dbus.service
@@ -94,4 +96,13 @@ def get_interface(interface, path):
 
 def get_notifications_interface():
 	'''Returns the notifications interface.'''
-	return get_interface('org.freedesktop.Notifications','/org/freedesktop/Notifications')
+	return get_interface('org.freedesktop.Notifications',
+		'/org/freedesktop/Notifications')
+
+if supported:
+	class MissingArgument(dbus.DBusException):
+		_dbus_error_name = _GAJIM_ERROR_IFACE + '.MissingArgument'
+	
+	class InvalidArgument(dbus.DBusException):
+		'''Raised when one of the provided arguments is invalid.'''
+		_dbus_error_name = _GAJIM_ERROR_IFACE + '.InvalidArgument'
diff --git a/src/common/exceptions.py b/src/common/exceptions.py
index ca6bf51c9..4731829f5 100644
--- a/src/common/exceptions.py
+++ b/src/common/exceptions.py
@@ -2,16 +2,10 @@
 ##
 ## Contributors for this file:
 ## - Yann Le Boulanger <asterix@lagaule.org>
-## - Nikos Kouremenos <kourem@gmail.com>
+## - 
 ##
-## Copyright (C) 2003-2004 Yann Le Boulanger <asterix@lagaule.org>
-##                         Vincent Hanquez <tab@snarc.org>
-## Copyright (C) 2005 Yann Le Boulanger <asterix@lagaule.org>
-##                    Vincent Hanquez <tab@snarc.org>
-##                    Nikos Kouremenos <kourem@gmail.com>
-##                    Dimitur Kirov <dkirov@gmail.com>
-##                    Travis Shirk <travis@pobox.com>
-##                    Norman Rasmussen <norman@rasmussen.co.za>
+## Copyright (C) 2005-2006 Yann Le Boulanger <asterix@lagaule.org>
+##                         Nikos Kouremenos <kourem@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published
diff --git a/src/notify.py b/src/notify.py
index db8032891..b50aed37c 100644
--- a/src/notify.py
+++ b/src/notify.py
@@ -25,7 +25,7 @@ import gtkgui_helpers
 from common import gajim
 from common import helpers
 
-import dbus_support
+from common import dbus_support
 if dbus_support.supported:
 	import dbus
 	import dbus.glib
diff --git a/src/remote_control.py b/src/remote_control.py
index 0ce901e24..bbb6990c0 100644
--- a/src/remote_control.py
+++ b/src/remote_control.py
@@ -23,7 +23,7 @@ from common import helpers
 from time import time
 from dialogs import AddNewContactWindow, NewChatDialog
 
-import dbus_support
+from common import dbus_support
 if dbus_support.supported:
 	import dbus
 	if dbus_support:
@@ -228,7 +228,7 @@ class SignalObject(dbus.service.Object):
 		message to 'jid', using account(optional) 'account' '''
 		jid, account = self._get_real_arguments(args, 2)
 		if not jid:
-			# FIXME: raise exception for missing argument (dbus0.35+)
+			raise MissingArgument
 			return None
 		jid = self._get_real_jid(jid, account)
 
@@ -277,7 +277,7 @@ class SignalObject(dbus.service.Object):
 		status, message, account = self._get_real_arguments(args, 3)
 		if status not in ('offline', 'online', 'chat', 
 			'away', 'xa', 'dnd', 'invisible'):
-			# FIXME: raise exception for bad status (dbus0.35)
+			raise InvalidArgument
 			return None
 		if account:
 			gobject.idle_add(gajim.interface.roster.send_status, account, 
@@ -305,7 +305,7 @@ class SignalObject(dbus.service.Object):
 		if not isinstance(jid, unicode):
 			jid = unicode(jid)
 		if not jid:
-			# FIXME: raise exception for missing argument (0.3+)
+			raise MissingArgument
 			return None
 		jid = self._get_real_jid(jid, account)
 
diff --git a/src/roster_window.py b/src/roster_window.py
index 03c0b457d..04fdaccd6 100644
--- a/src/roster_window.py
+++ b/src/roster_window.py
@@ -40,7 +40,7 @@ from chat_control import ChatControl
 from groupchat_control import GroupchatControl
 from groupchat_control import PrivateChatControl
 
-import dbus_support
+from common import dbus_support
 if dbus_support.supported:
 	from music_track_listener import MusicTrackListener