compiz problem


I have nvidia geforce 8400M GT on my Sony Vaio (vgn-fz285UB). I have got compiz fusion with KDE 4.1 in opensuse 11.1. However, it is very unstable. At times the task bar and the title bar vanish and
the window manager becomes very difficult to use. Moreover, I cannot get emerald theme manager to work. Is there any workaround? Please suggest.