Undefined symbols using OSS ati-driver: mismatching driver-files

Binary package hint: xserver-xorg-driver-ati

Beryl/Compiz does not work for me, even though nearly everything is setup correct.
3d works ppracer works, glxgears works... but almost. It turns real slow, but gives good-correct frame-rates.
It gives me the following error:

libGL: XF86DRIGetClientDriverName: 5.2.0 r200 (screen 0)
libGL: OpenDriver: trying /usr/lib/dri/r200_dri.so
libGL error: dlopen /usr/lib/dri/r200_dri.so failed (/usr/lib/dri/r200_dri.so: undefined symbol: _glapi_add_dispatch)
libGL error: unable to find driver: r200_dri.so
libGL: XF86DRIGetClientDriverName: 5.2.0 r200 (screen 0)
libGL: OpenDriver: trying /usr/lib/dri/r200_dri.so
libGL error: dlopen /usr/lib/dri/r200_dri.so failed (/usr/lib/dri/r200_dri.so: undefined symbol: _glapi_add_dispatch)
libGL error: unable to find driver: r200_dri.so

while the driverfile is there. But there seems something wrong with the symbols in it. Now it seems that this has something to do with not-matching versions of X/Mesa/ati-driver (I use the open-source one). Yes, I reïnstalled the ati and mesa-glx/dri several times.

I see this issue from this page, section 'Userspace setup'
http://dri.freedesktop.org/wiki/DriTroubleshooting

Serious technical support would be appreciated, or a serious bug-destoyer :-)

To me, this is a bug, beacause Ubuntu-repos should not allow mismatching files to happen. It seems to have occurred because I first used fglrx. But furthermore I never messed around with 3rd party compiled drivers et cetera...