LR doesn’t strictly need Apple Quicktime to import .MOV files, except in some circumstances. Maybe try uninstalling Quicktime?
Some video troubleshooting guidance from Adobe: http://helpx.adobe.com/lightroom/kb/troubleshoot-video-issues-lightroo m-4.html
There is also a known issue with Norton Anti-Virus: http://helpx.adobe.com/lightroom/kb/video-import-stop-or-error.html