I had a few apps originally purchased through the App Store that got corrupted. I removed them with the intent of re-installing them from the App Store, but it seems that the App Store thinks they're still/already installed. The action button is disabled. I found a related question, but the solution didn't work for me.

The app doesn't exist in either /Applications or /Downloads. Any ideas what I might be able to do to re-download the app?

Thanks.