airspy_set_samplerate() failed: AIRSPY_ERROR_LIBUSB on Ubuntu Mate 16.04

[rbw42]

Hi,

I'm trying to run the airspy WSPRd on a freshly installed Ubuntu MATE 16.04 machine (with updates installed). I've installed the airspy and libairspy-dev packages and compiled the code. The airspy device is detected OK:
airspy_lib_version: 1.0.7

Found AirSpy board 1
Board ID Number: 0 (AIRSPY)
Firmware Version: AirSpy NOS v1.0.0-rc10-0-g946184a 2016-09-19
Part ID Number: 0x6906002B 0x00000030
Serial Number: 0x644064DC233491CD
Supported sample rates:
10.000000 MSPS
2.500000 MSPS
Close board 1

And I can capture data:
airspy_rx -r /dev/null -a 1 -n 25000000
Device Serial Number: 0x644064DC233491CD
Stop with Ctrl-C
Streaming at 2.50 MSPS
....

But when I try to run the WSPR daemon:
rwayth@vanilli:/usr/local/airspy-wsprd$ ./airspy_wsprd -f 50.293M -c VK6FRTL -g OF77wx -l 10 -m 10 -v 10
airspy_set_samplerate() failed: AIRSPY_ERROR_LIBUSB (-1000)

I also tried blacklisting the kernel module, but that didn't help. Any suggestions much appreciated.

Cheers,
Randall