Sorry there was a problem with this download. We have taken the steps to notify our release team of this problem. At this time the download link in question has been updated and is working.
Again sorry for the inconvenience, and thanks for reporting this.
Also this appears to be a duplicate of post of https://community.atlassian.com/t5/Fisheye-Crucible-questions/I-am-unable-to-download-latest-4-5-1-Crucible/qaq-p/679244