Description of problem:
no system tray detected so it crashes

Version-Release number of selected component:
hplip-gui-3.18.6-1.fc28

Additional info:
reporter:       libreport-2.9.5
cmdline:        /usr/bin/python3 /usr/bin/hp-wificonfig -d hp:/usb/HP_LaserJet_CP1025nw?serial=00000SV03210S
crash_function: __writeChannel
exception_type: base.g.Error
executable:     /usr/bin/hp-wificonfig
interpreter:    python3-3.6.6-1.fc28.x86_64
kernel:         4.17.19-200.fc28.x86_64
runlevel:       N 5
type:           Python3
uid:            1000

Truncated backtrace:
wifisetupdialog.py:843:showIOError:TypeError: 'Error' object does not support indexing

Traceback (most recent call last):
  File "/usr/share/hplip/ui5/wifisetupdialog.py", line 274, in showNetworkPage
    adaptor_list = self.wifiObj.getWifiAdaptorID(self.dev)
  File "/usr/share/hplip/base/LedmWifi.py", line 97, in getWifiAdaptorID
    ret = getAdaptorList(dev)
  File "/usr/share/hplip/base/LedmWifi.py", line 60, in getAdaptorList
    paramsList,code = readXmlTagDataFromURI(dev,URI,'<io:Adapters', '<io:Adapter>')
  File "/usr/share/hplip/base/LedmWifi.py", line 499, in readXmlTagDataFromURI
    dev.writeMarvell_EWS(data)
  File "/usr/share/hplip/base/device.py", line 2228, in writeMarvell_EWS
    return self.__writeChannel(self.openMarvell_EWS, data)
  File "/usr/share/hplip/base/device.py", line 2258, in __writeChannel
    raise Error(ERROR_DEVICE_IO_ERROR)
base.g.Error: ('Device I/O error', 12)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/share/hplip/ui5/wifisetupdialog.py", line 719, in NextButton_clicked
    self.showNetworkPage()
  File "/usr/share/hplip/ui5/wifisetupdialog.py", line 276, in showNetworkPage
    self.showIOError(e)
  File "/usr/share/hplip/ui5/wifisetupdialog.py", line 843, in showIOError
    FailureUI(self, self.__tr("<b>An I/O error occurred.</b><p>Please check the USB connection to your printer and try again.</p>(%s)" % str(e[0])))
TypeError: 'Error' object does not support indexing

Local variables in innermost frame:
e: Error('Device I/O error', 12)
self: <ui5.wifisetupdialog.WifiSetupDialog object at 0x7f7782d0b288>