Can’t click links on right side of plugin installation popups (like install)

When browsing through plugins to install, there’s an “install” link on the right side of each plugin listing. I click it and a lightbox thing opens up that says “Plugin Information”. This is odd but I can click all the links on the left side of the popup window under “Description”. But I can’t click anything on the right side, including the big red “Install” button at the top or any of the links below that, including the links to the plugin hompage.

This problem is very odd but extremely annoying, and totally consistent. I’m using Firefox and the right side links worked a few weeks ago but not any more. This is the same situation at multiple different computers too so it doesn’t seem to be a localized problem. I tried deactivating most of my plugins thinking there may be interference but nothing helps. I also tried this on Google Chrome browser and I have the exact same issue. However, this problem does not occur in Microsoft Internet Explorer. Odd.

This problem means I can’t use Firefox or Chrome to automatically install plugins. Anybody else see this issue before or know how to solve it.