This message seems to occur on random occasions under Windows 7 and 8.
Don't close NoiseMap if this happens. Just unplug and replug the dongle, wait a moment and then click Retry.
It seems that the problem is caused by a power saving feature built into Windows.
You can prevent the problem occurring by going to Device Manager (located in "Control Panel\System and Security\System" and going to Universal Serial Bus Controllers
Most systems have several of these. Select them one at a time and open their properties.
If they have a Power Management Tab, then open this and UNCHECK "Allow the computer to turn of this device to save power"
This should resolve the issue.
It has been noted that the problem seems to go away once Windows learns about the dongle (Yes, it does remember devices plugged into the USB ports: presumably to make it quicker to load the right driver when a device is connected.) Unfortunately, if there is no communication with the dongle for a while, its seems that power saving kicks in.
