Some Maps Don't Work

[twilight]

So I've downloaded a bunch of maps and put 'em in my abse folder...some of em work fine...some of 'em show up but when we try to change the map to them nothing happens...and some don't show up at all. Any ideas?

[Survivor]

They were either saved as .zip instead of .pk3 or, if they do not show up in the selection menu but are playable, do not have a .arena file.

[Mantra]

Or, the server you're trying to play them on doesn't have them.
Try doing:
/devmap mapname
In console. Check the ones that don't show up, those probably didn't download as pk3 files, but as zip.
Note those down, then go to your base folder.
Check those map files, if you see a .zip a the end, remove it.
If you don't, right click on the file and go to propriety and look at the file name, it might be a .zip file there, remove it.
Otherwise, they might be unfinished maps.

Some beta maps, as stated, do not have a .arena file, so they won't appear in the drop menu. You'll need to vote them manually.
Do
/callvote map mapname
in console, if the server doesn't ahve it, nothing will happen(In most case you won't be able to vote the map since some servers keep you from voting maps that it doesn't have.

Now have fun playing new maps!