Comment 9 for bug 568015

@coldReactive: I did not install the latest drivers. I still use the drivers that came with ubuntu and only replaced the control file located in /etc/ati

I've only downloaded the latest drivers to extract the control file, not to install it :)

So keep your (working) drivers and extract the latest *.run file by adding the option --extract in a terminal.
Then replace your current "control" file with the extracted one (as described above)

Please notice, that this only may help, if your graphics card is already WORKING and you only want to get rid of the watermark.

If your graphics card stopped working with the drivers, that come with ubuntu 10.04 you could try to install an older one and then replace the control file.