lmc really should support other installation sources like nfs.
lorax-21.26-1.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/lorax-21.26-1.fc21
lorax-21.26-1.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.