Hello. I have got kde4.1.1 from packages. Maybe my problem is the same, but I have no taskbar at all. Only blank space. I think that plasma daemon is incomplete. There is no ~/.kde/config/plasma-appletsrc file too. How can I restore taskbar?
system - FreeBSD 7.1-beta2
video - NVidia GeForce 8800
xorg videodriver - nv
The nv driver seems to be a little bit iffy, given how there was another similar thread where firefox 3 was partially transparent. It's here, and the tips there are probably worth testing.
edit: Ah, gx is using the nvidia driver. Try enabling or disabling compositing in kwin and see if it does anything. (Rightclick a window title, Configure Window Behavior, Desktop Effects -> Enable desktop effects)