Hi, Unfortunately it was found recently that 0.15.1 has a regression that prevents rendering. 0.15.2 is out with a one-liner fix for it. Tarballs are available on http://ftp.gnome.org/pub/GNOME/sources/pitivi/0.15/ I applied the one-liner fix on my Fedora 16 and Fedora 17 machines and it does seem to make things work. Sorry for the trouble!
pitivi-0.15.2-1.fc16 has been submitted as an update for Fedora 16. https://admin.fedoraproject.org/updates/pitivi-0.15.2-1.fc16
pitivi-0.15.2-1.fc15 has been submitted as an update for Fedora 15. https://admin.fedoraproject.org/updates/pitivi-0.15.2-1.fc15
pitivi-0.15.2-1.fc17 has been submitted as an update for Fedora 17. https://admin.fedoraproject.org/updates/pitivi-0.15.2-1.fc17
Package pitivi-0.15.2-1.fc17: * should fix your issue, * was pushed to the Fedora 17 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing pitivi-0.15.2-1.fc17' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2012-7261/pitivi-0.15.2-1.fc17 then log in and leave karma (feedback).
pitivi-0.15.2-1.fc16 has been pushed to the Fedora 16 stable repository. If problems still persist, please make note of it in this bug report.
pitivi-0.15.2-1.fc15 has been pushed to the Fedora 15 stable repository. If problems still persist, please make note of it in this bug report.
pitivi-0.15.2-1.fc17 has been pushed to the Fedora 17 stable repository. If problems still persist, please make note of it in this bug report.