Midlet autostart on a tag nearby problem

[Ltsolo]

Hello All. I've got strange problem with the application autostart on a tag nearby. I'm using the following pair:

String pushEntry = "nfc:undefined_format";
String filter = "*";//"nfc:rf;type=simpletag;uid=*";
PushRegistry.registerConnection(pushEntry, myAppClass, filter);

Also I'm doing:

dm.addTargetListener(this, TargetType.RFID_TAG);
dm.addTransactionListener(this);

Good thing is that the phone I have (Nokia 6131) starts my application on a tag but this happens about once per twenty tries (I move a tag to the phone twenty times and only once the application starts). In all the rest nineteen cases it gives "Unknown service type" message.

Can you please advice the reason or a way to overcome?