I made another learning mistake haha. I put the latest udk version on my computers. However, when I tried to test it out in multiplayer, to my surprise, it didn't' work.
In the december release, the multiplayer start game button doesn't work. At least not on my computers.
Unfortunately, you can't play maps in older versions of udk if they were created in newer versions. My november release of udk has no trouble starting multiplayer games but I've made alot of changes to my map using december's release. I'm not very willing to redo all the changes either.
Hopefully, when they release January 2012 version, it will be working again. Next time, I'll check out the newer releases thoroughly before making any changes to my maps. Lesson learned.
Now that's annoying. If they could have released a patch for it, maybe it would have been better.