You can't enable cheats on a server unless your are the admin of that server (ie: you've logged in admin access with Rcon, using your Rconpassword; though if it's hosted locally or non-dedicated you may not need to enter the password to admin your own server).
You obviously can't use cheats on someone else's server unless they gave you the admin password. ;)
Devmapall ONLY works for Single Player, and it doesn't work with the 1.01 patch (you use HelpusObi 1 instead).
In MP the maps need to be loaded in cheat mode to work (devmap <mapname>).
Bow, Gloat, Flourish, Meditate, and Taunt are not "cheats" they are just animated taunts that work in both SP and MP (though Gloat and Flourish are designed to work with sabers). Mods call these "emotes" though they are referred to as "taunts" by the official game literature.
Drive_ATST and Fly_Xwing are JK2 cheats, they don't work in JA. A lot of sites were desperate to post cheats when JA came out, and some people may have also sent them false info. Needless to say, they copied and pasted the JK2 cheats onto the JA pages, when in fact they don't all work. I've tried emailing sites like gamewinners, and they seem to simply ignore such emails calling for corrections, sadly.
If you want a list of working cheats for JA, try this thread sticky:
http://www.lucasforums.com/showthread.php?s=&threadid=111511)
(includes both SP and MP cheats)
We've found just about everything you could think of since the game came out. It's all there, even if you have to read or search a bit (Skinwalker is still working on the compiled list of cheats in one concise document I think!).