It seems that -DVTK_USE_QT=ON is required in vtk-5.6 to build the related qt stuff (tested with vtk-5.6.1).
The package vtk-qt built in latest rawhide has no files. Did not test Fedora 14. Needless to say, this breaks quite a few apps.
I confirm this bug, it breaks some applications.
I tried add '-DVTK_USE_QT=ON', it works: http://koji.fedoraproject.org/koji/taskinfo?taskID=2686365
vtk-5.6.0-38.fc14 has been submitted as an update for Fedora 14. https://admin.fedoraproject.org/updates/vtk-5.6.0-38.fc14
vtk-5.6.0-38.fc14 has been pushed to the Fedora 14 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with su -c 'yum --enablerepo=updates-testing update vtk'. You can provide feedback for this update here: https://admin.fedoraproject.org/updates/vtk-5.6.0-38.fc14
vtk-5.6.0-38.fc14 has been pushed to the Fedora 14 stable repository. If problems still persist, please make note of it in this bug report.