Thats because the code is too old.
search the script for "remove" and replace it with ent_remove.
Thanks! That worked perfectly. Now, I'm trying to get the game done and published...but there is one problem.
I am following Locoweed's Multiplayer Tutorial and the final 'chapter' of the tutorial show how to build the game to work properly. However, when I try and run the BiosphereIV.exe, the game launches another BiosphereIV.exe instead of the multiplayer.exe. When run seperately, the multiplayer.exe works fine...but I'm not sure what to do to get it to work now.