Yeah, "devmapall" doesn't work anymore. It was part of Jedi Outcast, but they changed it to "helpusobi 1" for JA. But that's single player anyhow.
devmap <map name> is the proper way to do it in multiplayer. The admin loads the map with cheats enabled and then you can type in the cheats (note that not all single player cheats work or are the same in multiplayer, and some can cause the server to become unstable or crash). You may also need to use map_restart after entering it for the cheats to be properly loaded. Remember, when they're on, ANYBODY can use 'em. Reload the map with the map <mapname> command (and map_restart if necessary) to go back to normal.