Line in is always "Currently Unavailable"

Hi,

I tried using my USB 5.1 sound card to do some T/S measurement, my measurement jig is connected to "front out" and "line-in". However Limp always fails to open the line-in device. When I saw the device in ControlPanel->Sound->Recording, it always is "Currently Unavailable"

Can anyone please help to resolve the problem.

Thanks and Regards,
WonderfulAudio