MP doesnt allow dyanmic objects/entities.
To get lights, create the arena in Single player, place lights etc, then go to File>Preferences>Change to MP.
Remember, normally you can go to File>Build game and change the menu buttons etc, but
DO NOT do this when making an MP arena. You will need to compile the game, and then go to the folder, find the relevent files, and change the button using Photoshop, GIMP etc. This is a nasty bug, and will switch the menu to single player, and you will have to restore the game file (cant remember precise name).
If any of the kids do this, you need to do the following to restore.
Quote: "This is due to a bug in the editor code, do NOT ever edit an MP game's hud with the editor. It will replace the file with an SP games file and then you will lose your MP abilitys. Thankfully, I have uploaded this file."
Click here for the download.
Also, while you're at it, read this;
Quote: "http://forum.thegamecreators.com/?m=forum_view&t=74027&b=24"
Some things are out of date, EG riker 9. Dont even ask.