将ubuntu从10.04升级到10.10后，compiz特效出不来了。

[hqwxyz]

在10.04下一切都正常，可是通过网络升级到10.10（而不是重新安装）后，compiz特效出不来了。在“外观首选项”中的“正常”和“扩展”都显示“无法启用桌面效果”。机器是dell inspiron 640m，显卡是intle的945gm

运行ubuntu tweak中的“compiz设置”，显示如下错误：
Distribution: Ubuntu 10.10 maverick
Application: Ubuntu Tweak 0.5.10
Desktop: gnome

Traceback (most recent call last):
File "/usr/lib/python2.6/dist-packages/ubuntutweak/mainwindow.py", line 502, in setup_notebook
page = module()
File "/usr/lib/python2.6/dist-packages/ubuntutweak/modules/compiz.py", line 325, in __init__
self.create_interface()
File "/usr/lib/python2.6/dist-packages/ubuntutweak/modules/compiz.py", line 343, in create_interface
hbox.pack_start(self.create_edge_setting(), True, False, 0)
File "/usr/lib/python2.6/dist-packages/ubuntutweak/modules/compiz.py", line 475, in create_edge_setting
self.TopLeft = self.create_edge_combo_box("TopLeft")
File "/usr/lib/python2.6/dist-packages/ubuntutweak/modules/compiz.py", line 447, in create_edge_combo_box
if CompizPlugin.is_available(k, v):
File "/usr/lib/python2.6/dist-packages/ubuntutweak/modules/compiz.py", line 127, in is_available
getattr(cls.context.Plugins[name], target).has_key(setting)
File "compizconfig.pyx", line 945, in compizconfig.Plugin.Display.__get__
File "compizconfig.pyx", line 766, in compizconfig.Plugin.Update
KeyError: 'active_plugins'

求达人指点！谢谢！