Updates API - Error parsing request body

My app is getting following error for quite a few requests.

{u'error': {u'lang': u'en-US', u'detail': u'Error parsing request body(Invalid APP or Invalid Data):', u'uri': u'http://social.yahooapis.com/v1/errors/400', u'description': u'Malformed syntax or a Bad query'}}

Requests with similar data to Yahoo Meme go fine via YQL. I guess Yahoo Updates API filter has become strict in terms of what is malformed. My app is using the insertUpdate function from Yahoo Python Social sdk. .

Below is the body of a sample insertUpdate that is failing:

******************************
body:
{ "updates":
[
{
"class": "app",
"collectionType": "guid",
"description": "DonVuitton_: RT @Donvuitton_ New post: Nadja Benaissa \'GUILTY\' Spreading HIV! http://bit.ly/aS2jHH",
"suid": "ugc4",
"link": "http://twitter.com/DonVuitton_/statuses/22198315583",
"source": "APP.G946Jb3e",
"pubDate": "1282846022",
"title": "posted DonVuitton_: RT @Donvuitton_ New post: Nadja Benaissa \'GUILTY\' Spreading HIV! http://bit.ly/aS2jHH",
"type": "update",
"collectionID": "NQY6YYAWJ7QNIP6Y4WUCDKKRRA"
}
]
}
******************************