Villagers Gone, Immediately Despawn when using eggs?

I opened my server after updating to Minecraft 1.8.1 and attempted to play and noticed that there was not a single villager anywhere on my server at all. The server is a rather large server and villagers play a big part in the stuff I have built on it. I later updated to the new Minecraft Snapshot and noticed the problem still existed.

Anyway, I try to spawn villagers and the game despawns them immediately. This really poses a problem for my server and the role villagers play in my construction of cities and other things that I have built.