Please try this:

1. Turn off Synergy.

2. Run HotkeyNet as admin on Vista machine.

3. Make sure both WoWs are full-screen because the following assumes they are.

4. Raise ClickMouse delays to 100 100 on BOTH machines.

5. Press this new hotkey:

Code:
<Hotkey LButton>
<PassThrough>
<SendPC IP_ADDRESS>
<SendFocusWin>
<ClickMouse %TriggerMainKey%>
If that doesn't work, please paste the red or blue messages from both machines here.