installer crashes at configure mythtv

Traceback (most recent call last):
  File "/usr/lib/ubiquity/bin/ubiquity", line 210, in <module>
    main()
  File "/usr/lib/ubiquity/bin/ubiquity", line 207, in main
    install()
  File "/usr/lib/ubiquity/bin/ubiquity", line 58, in install
    ret = wizard.run()
  File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 378, in run
    self.process_step()
  File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 1032, in process_step
    self.progress_loop()
  File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 760, in progress_loop
    (ret, realtb))
RuntimeError: Install failed with exit code 1
Traceback (most recent call last):
  File "/usr/share/ubiquity/install.py", line 1584, in <module>
    install.run()
  File "/usr/share/ubiquity/install.py", line 357, in run
    self.configure_mythbuntu()
  File "/usr/share/ubiquity/install.py", line 985, in configure_mythbuntu
    ret = control.run()
  File "/usr/lib/ubiquity/ubiquity/components/mythbuntu_apply.py", line 91, in run
    pattern = re.compile(patternline)
UnboundLocalError: local variable 'patternline' referenced before assignment