invalid value for keybinding causes terminator to crash

I wanted to unset some keybindings so based on terminator_config man page I entered the value "Unbound" for the key (same as default value for switch_to_tab_N). Apparently this doesnt work and causes terminator to crash.
I am using terminator 0.13 on ubuntu 9.10 from the package repo.

[~]% terminator
Traceback (most recent call last):
  File "/usr/bin/terminator", line 163, in <module>
    options.geometry, options.hidden, options.forcedtitle)
  File "/usr/share/terminator/terminatorlib/terminator.py", line 307, in __init__
    self.keybindings.configure(self.conf.keybindings)
  File "/usr/share/terminator/terminatorlib/keybindings.py", line 63, in configure
    self.reload()
  File "/usr/share/terminator/terminatorlib/keybindings.py", line 83, in reload
    raise ex
terminatorlib.keybindings.KeymapError: Keybinding 'prev_tab' invalid: Key 'Unbound' is unrecognised
[~]% terminator -v
terminator 0.13
[~]%