Ok, forget about that one. I crosschecked on another machine also running Fedora 10 and there the benchmark works as expected. The difference was that the machine that showed the error had a beta sample of the nVidia driver installed while the working machine is running version 180.51. I noticed the flaw because the error machine always reported "OpenGL: N/A" in the reports while the working machine detects OpenGL without problems.
The only remaining disappointment is that the test stops with the message that the average frame rate is 0.00 and it then doesn't offer to show the results.