Java won't allow Keepvid applet

I am trying to download a video from YouTube (do not rage about rights, the maker has allowed me to take the video) and Java absolutely will not allow the Keepvid applet to run. When the dialog box pops up asking if I would like to allow it, the "allow" button is greyed out and it has a message stating that java will not allow any access to this applet because it is not trusted. I pulled up the details and selected "always trust". I even went to keychain access and verified the applets trusted status there. I have tried wiping the cache and cookies and reading java trouble shooting tips. I'm using google chrome... Please help.

Thank you very much for your help!