Purchased add-on. Showing in my project list on c5 but not on my actual site (so can't install)

Permalink
I've never had this happen with a purchased add-on before. Usually works just fine. In this case, however, I select the license, associate it with my site, it shows up in my list of themes & add-ons but then when I go to Dashboard - Install ... it's not there. And yet the other add-ons I've purchased have worked without any problem.

Any help would be greatly appreciated.