Mapinfo needs to go in pball/maps/mapinfo/beta (but no worries, I put it in the right spot). The //'s aren't necessary, either. The game just scans for [mapinfo].
Wow, you really went all out on those windows. I noticed a slight bit of metal showing up on some of the wood frames, but they look nice other than that.
I'd make the flag cap area taller. Basically if you touch your flag you should cap. It's really easy to overshoot it right now.
Love the sludge texture being used under the water. Good idea. You might consider even expanding it along the metal edges, too.
For your custom textures, you should consider making HR4 versions, if possible. Right now they're kind of halfway between high res and low res textures. Also, up the jpeg quality up when saving them. Try using about 90-96%. Compression artifacts are really visible in the jail texture.
Great work overall. I'm not sure what else to add other than maybe tweak the areas visible from high places a little bit. Like the top of the building just gets cut off by sky when looking at it from the top of the jail. Not that big of a deal, though.
I've got it up in rotation on the beta server.