HotkeyNet's script language changed a lot in the last three builds, so old scripts need to be changed. Here's a new script for three Warhammers on three PCs. This requires build 130 or higher.

You can download here: Download Hotkeynet

Code:
//===================================================================
// Sample HotkeyNet script for three Warhammers on three PCs.
// Requires HotkeyNet build 130 or higher.
// For more info, see www.hotkeynet.com 
//===================================================================

//-----------------------------------------------------------
// Define labels for the two remote copies
//-----------------------------------------------------------
<Label w2 PUT_IP_ADDRESS_HERE SendWin Warhammer>
<Label w3 PUT_IP_ADDRESS_HERE SendWin Warhammer>

//-----------------------------------------------------------
// Define hotkeys for keys that get broadcast to all
// three Warhammers. Use ScrollLockOn so you can toggle
// these hotkeys off and on by pressing Scroll Lock. 
//-----------------------------------------------------------
<Hotkey ScrollLockOn A-Z, 0-9, F1-F12 except up, down, left, right>
<PassThrough> 
<SendLabel w2, w3>
<Key %Trigger%>

//-----------------------------------------------------------
// Use MovementHotkey to name movement keys that will
// get sent to all Warhammers. Add more keys if you want.
// Use ScrollLockOn so you can toggle these hotkeys off
// and on by pressing Scroll Lock. 
//-----------------------------------------------------------
<MovementHotkey ScrollLockOn up, down, left, right>
<SendLabel w2, w3>
<Key %Trigger%>

//-----------------------------------------------------------
// Define hotkeys to broadcast mouse clicks with left button
// and right button. The clicks will get broadcast only when
// you hold down Oem3 key (on U.S. keyboards, that's the
// squiggle key in upper left corner).
//---------------------------------------------------------
<UseKeyAsModifier Oem3> 
<Hotkey Oem3 LButton>
<SendWinM WoW1>
<ClickMouse LButton> 
<SendWinM WoW2>
<ClickMouse LButton>

<Hotkey Oem3 RButton>
<SendWinM WoW1>
<ClickMouse RButton> 
<SendWinM WoW2>
<ClickMouse RButton>