ZombieMod is in v3 beta. 2.x.x is completely dead (blame valve).

3.0.0 G - Zombie Mod

It does not work on Linux servers right now though.

Zombie: Reloaded can easily be configured to the settings that everyone is used to though.

I also have a copy of the ZombieMod Beta, if you would like it, hit me up on steam fool.

- Dot.