$my_data = str_replace('\\"', '"', $my_data);
$json = new Services_JSON();$json->decode($my_data);
This is due to the JSON parser unable to interpret escaped quotes. This is an excellent encoder and decoder, but this issue caused a few days of grief.
This code is for a legacy system with an outdated version of PHP. Newer versions of PHP should have support for JSON decoding and JSON encoding.