this module is error while loading windows manager settings page

Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/ubuntutweak/mainwindow.py", line 393, in setup_notebook
    page = module()
  File "/usr/lib/pymodules/python2.6/ubuntutweak/modules/metacity.py", line 206, in __init__
    min=0, max=1, digits=2),
  File "/usr/lib/pymodules/python2.6/ubuntutweak/common/factory.py", line 49, in create
    return getattr(cls, 'do_composite_create')(widget, **kwargs)
  File "/usr/lib/pymodules/python2.6/ubuntutweak/common/factory.py", line 60, in do_composite_create
    new_widget = globals().get(widget)(**kwargs)
  File "/usr/lib/pymodules/python2.6/ubuntutweak/widgets/widgets.py", line 143, in __init__
    self.set_value(self.__setting.get_value())
  File "/usr/lib/pymodules/python2.6/ubuntutweak/conf/gconfsetting.py", line 88, in get_value
    return self.__type(None)
TypeError: float() argument must be a string or a number

Architecture: i386
CheckboxSubmission: 5405cfd14c96f5683bd365dd8b1f818f
CheckboxSystem: d00f84de8a555815fa1c4660280da308
DistroRelease: Ubuntu 9.10
InstallationMedia: Ubuntu-Netbook-Remix 9.10 "Karmic Koala" - Release i386 (20091028.4)
NonfreeKernelModules: wl
Package: ubuntu-tweak 0.5.1-1~karmic1
PackageArchitecture: all
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANG=en_US.UTF-8
ProcVersionSignature: Ubuntu 2.6.31-20.57-generic
Tags: ubuntu-unr
Uname: Linux 2.6.31-20-generic i686
UserGroups: adm admin audio cdrom dialout dip fax fuse lpadmin netdev plugdev sambashare sudo tape video