Problem:

|Traceback (most recent call last):
  File "/usr/share/hplip/ui4/setupdialog.py", line 1245, in NextButton_clicked
    self.showAddPrinterPage()
  File "/usr/share/hplip/ui4/setupdialog.py", line 680, in showAddPrinterPage
    self.readwriteFaxInformation()
  File "/usr/share/hplip/ui4/setupdialog.py", line 1069, in readwriteFaxInformation
    self.fax_name_company = unicode(d.getStationName())
  File "/usr/share/hplip/fax/ledmfax.py", line 134, in getStationName
    return self.readAttributeFromXml("/DevMgmt/FaxConfigDyn.xml",'faxcfgdyn:faxconfigdyn-faxcfgdyn:systemsettings-dd:companyname')
  File "/usr/share/hplip/base/device.py", line 2505, in readAttributeFromXml
    return str(xmlDict[attribute])
KeyError: 'faxcfgdyn:faxconfigdyn-faxcfgdyn:systemsettings-dd:companyname'
\

Cause:
My company name in my Fax Settings had an ampserand (&) in it.
e.g.

JA & LK McDonald

Fix:
Remove the ampersand to complete the install
e.g.

JA LK McDonald

End note:
Oh and incidentally network faxing now appears to work (at least I could connect and configure using hp-sendfax)