Index: message.py
===================================================================
--- message.py	(Revision 48275)
+++ message.py	(Arbeitskopie)
@@ -116,7 +116,10 @@
 		if _type == Message.REQUEST:
 			type = 'REQUEST'
 		if mimetype == MIMETYPE_JSON:
-			data = json.dumps( body )
+			try:
+				data = json.dumps( body )
+			except UnicodeDecodeError:
+				data = json.dumps(_fix_encoding(body))
 		else:
 			data = body
 		args = ''
@@ -316,6 +319,21 @@
 			del body['options']
 		return Message._formattedMessage(self._id, self._type, self.mimetype, self.command, body, self.arguments)
 
+
+def _fix_encoding(data):
+	if isinstance(data, bytestring):
+		try:
+			data.decode('utf-8')
+		except UnicodeDecodeError:
+			data = data.decode('iso8859-1').encode('utf-8')
+	elif isinstance(data, (list, tuple)):
+		data = data.__class__(_fix_encoding(d) for d in data)
+	elif isinstance(data, dict):
+		data = data.__class__((_fix_encoding(k), _fix_encoding(v)) for k, v in data.iteritems())
+
+	return data
+
+
 if __name__ == '__main__':
 	# encode
 	auth = Request( 'AUTH' )