Help: "There was an error downloading this map"

[Traslogan]

I recently reinstalled portal 2 after about 6-8 months of having it uninstalled, as I wanted to play a set of maps I made with the in-game mapping tool ages ago. Now, I installed it with them already subscribed, and when I got onto Portal 2, it attempted to re-download the first one. It never finishes, and when I tried again I just get the "error downloading this map" result. This does not happen to the other 4 of the 5 I wanted to try, but it's a series of tests, so I really want this one to work too.
As a note, I've tried verifying cache, unsubscribing and re-subscribing, and even went as far as to attempt a reinstall. Anyone know what is wrong?