Can't query RemoteDevice Error

Hi!
I used bluecove Api for bluetooth in java.
In my PC I used winsock bluetooth stack. In my application I want to connect my PC with PneuLogicProbe .
PneuLogicProbe send the digital value to my PC via bluetooth.
I finished that. Sometimes Can'tquery RemoteDevice exception in When I try to get getFriendlyName().
But sometimes its worked. Anybody know the reason please help me immeditely.
Its very urgend. please help me.

Thanks
Saravanan