Download Helper Not Installing Puntuado con 2 de 5 estrellas

I can't get this to install into Firefox 28. I add it, then I get a prompt to restart Firefox. Once restarted, Firefox opens up with the same add-on tab with the "Add to Firefox" button. Tried it a couple of times, but keeps going in the same loop. I also tried DLH beta version. Same results. I cleared out the cache, but nothing works.

Esta valoración es de una versión anterior del complemento (4.9.22.1-signed).