There are two things wrong:
1. the method call is:
$params_rt = array(
new XML_RPC_Value("9"),
new XML_RPC_Value("robot"),
new XML_RPC_Value("robot"),
new XML_RPC_Value(""),
new XML_RPC_Value(""),
$req_blocks_rt
);
That is you have one "" too much in your example, and
2. the method to call is QM.realtime and not QM.rt
$msg_rt = new XML_RPC_Message('QM.realtime', $params_rt);
If you do it like this, it works just fine!