worked just once

[fozzy123]

I followed your install guide and data transfer worked fine the first time but it wouldn't work the next time I tried.
here's the output

[MainThread] 2017-03-13 14:16:40,935 INFO Found device with vid(0x0fcf) pid(0x1008), but interface already claimed.
[MainThread] 2017-03-13 14:16:40,936 WARNING Failed to find Garmin nRF24AP2 (newer) USB Stick.
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/antd/cfg.py", line 92, in create_hardware
return hw.UsbHardware(id_vendor, id_product, bulk_endpoint)
File "/usr/local/lib/python2.7/dist-packages/antd/hw.py", line 61, in init
raise NoUsbHardwareFound(errno.ENOENT, "No available device matching vid(0x%04x) pid(0x%04x)." % (id_vendor, id_product))
NoUsbHardwareFound: [Errno 2] No available device matching vid(0x0fcf) pid(0x1008).
[MainThread] 2017-03-13 14:16:40,936 WARNING Looking for nRF24AP1 (older) Serial USB Stick.
Traceback (most recent call last):
File "/usr/local/bin/ant-downloader", line 11, in
load_entry_point('python-ant-downloader==13.2.24', 'console_scripts', 'ant-downloader')()
File "/usr/local/lib/python2.7/dist-packages/antd/main.py", line 75, in downloader
host = antd.cfg.create_antfs_host()
File "/usr/local/lib/python2.7/dist-packages/antd/cfg.py", line 118, in create_antfs_host
host = antfs.Host(create_ant_session(), keys)
File "/usr/local/lib/python2.7/dist-packages/antd/cfg.py", line 105, in create_ant_session
session = ant.Session(create_ant_core())
File "/usr/local/lib/python2.7/dist-packages/antd/cfg.py", line 101, in create_ant_core
return ant.Core(create_hardware())
File "/usr/local/lib/python2.7/dist-packages/antd/cfg.py", line 97, in create_hardware
return hw.SerialHardware(tty, 115200)
File "/usr/local/lib/python2.7/dist-packages/antd/hw.py", line 81, in init
self.dev = serial.Serial(port=dev, baudrate=baudrate, timeout=1)
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 261, in init
self.open()
File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 278, in open
raise SerialException("could not open port %s: %s" % (self._port, msg))
serial.serialutil.SerialException: could not open port /dev/ttyUSB0: [Errno 13] Permission denied: '/dev/ttyUSB0'

I appreciate all the work you put into all that. Thanks