Computer Name changes when waking from sleep

Hi,

I'm running OS X Lion Server on a Mac Mini 2ghz Core 2 Duo and every time it wakes from sleep I get a message saying "There is already a computer on the network named MacServer, renaming to MacServer (2)".

It only happens when waking from sleep. If I reboot or use the mini for hours without sleeping it's fine, but once it's gone to sleep it renames on wake. When it sleeps overnight it's named MacServer (5) by the morning, as it wakes up every two hours or so to re-register itself on the network and each time it renames itself.

I don't have any other compters on the network with the same name. The only other computer is a MBP and has a completly different name.

Here's my setup;

• My Mac Mini is wired via ethernet to a Time Capsule. AirPort is turned off (I've tried on and off).
• My Mac Mini has a static IP address (x.x.x.40) with DHCP for everything else (DNS, etc.)
• The Time Capsule is wired to an ADSL router via ethernet.
• The ADSL router manages DHCP and NAT, with IP pool x.x.x.2 through x.x.x.30.
• DHCP and NAT are turned off on the Time Capsule (bridged mode).
• Wireless is turned off on the ADSL router.
• Time Capsule is handling wireless.

I've tried resetting the ADSL router. I've tried resetting the Time Capsule (to factory defaults).

The problem seems to be with mDNSResponder, as the log seems to suggest that it is this daemon that thinks there's a duplicate computer name. I've even looked at the source code for mDNSResponder and the last mod-log entry suggests that a fix was put in for this issue in 2009. It doesn't look like it's fixed it, though.

I've tried doing a fresh install of OS Server several times now and, after the last install, it started happening before I got a chance to restore from a Time Machine backup. i.e. on a completly fresh install and assigning a completely new computer name.

Can anyone help me on this issue? It's driving me insane!