=== modified file 'mail/mail_message.py'
--- mail/mail_message.py	2011-12-19 16:54:40 +0000
+++ mail/mail_message.py	2012-01-24 13:14:32 +0000
@@ -453,7 +453,9 @@
 
             msg['body_text'] = body
         msg['attachments'] = attachments
-
+        # For encoding trouble: encode the string in unicode, ignoring unkown byte
+        if 'body_html' in msg and isinstance(msg['body_html'],str):
+            msg['body_html'] = unicode(msg['body_html'], errors='ignore')
         # for backwards compatibility:
         msg['body'] = msg['body_text']
         msg['sub_type'] = msg['subtype'] or 'plain'