ClearCase is dependent on the version of the kernel being used.
IBM/Rational has information at their website indicating which OS/Kernel
they support. Later versions of RHEL and SLES are on that list. I have
never seen Fedora listed there.
http://www-1.ibm.com/support/docview.wss?uid=swg21136950
If it runs on RHEL, you might try using CentOS instead of Fedora...
Chris