iMac keeps on waking up and sleeping over and over

Hi all, when 'wake for network access' is enabled, my 27" iMac wakes up and sleeps over and over. I want to retain wake for network access functionality but, as you will see below, it's generating serious problems. I have decided to tackle the issue now but need help!

When I initially put the computer to sleep, it wakes up immediately and stays on for a while with a black screen. Sometimes it stays on for ages, so that's not ideal in itself. I read here that this is something to do with Bonjour and the computer periodically registering itself with other things on the network (airport extreme, iphone etc.).

Anyway, I left it last night and checked the terminal using the 'wake reason' command this morning and found that it had woken up and gone back to sleep LOADS! As you can see from the terminal output, most of this waking up is from bonjour 'conflict resolution' instances, whatever that is. In any case, this is obviously much more than 'periodical' waking. It seems to be waking more like every ten minutes or so. It would probably use less energy and cause less wear on the disks to just leave it on!

I'm at a loss as to how to solve the problem - can anyone help?

Apr 14 02:38:58 Christopher-Holmess-iMac kernel[0] <Debug>: Wake reason: RTC (Alarm)

Apr 14 04:27:22 Christopher-Holmess-iMac kernel[0] <Debug>: Wake reason: RTC (Alarm)

Apr 14 04:27:54 Christopher-Holmess-iMac kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 04:27:55 Christopher-Holmess-iMac kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 04:33:28 Christopher-Holmess-iMac kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 04:33:28 Christopher-Holmess-iMac kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 04:43:35 Christopher-Holmess-iMac kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 04:43:35 Christopher-Holmess-iMac kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 04:53:48 Christopher-Holmess-iMac kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 04:53:48 Christopher-Holmess-iMac kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 04:58:45 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 04:58:45 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 05:08:58 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 05:08:58 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 05:24:03 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 05:24:03 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 05:29:01 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 05:29:01 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 05:34:07 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 05:34:07 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 05:39:11 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 05:39:11 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 05:55:57 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 05:55:57 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 06:06:02 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 06:06:02 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 06:27:48 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 06:27:48 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 06:34:16 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 06:34:16 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 06:39:23 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 06:39:23 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 06:44:28 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 06:44:28 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution

Apr 14 08:42:29 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: RTC (Alarm)

Apr 14 08:43:00 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Wake reason: GIGE (Network)

Apr 14 08:43:00 Christopher-Holmess-iMac-2 kernel[0] <Debug>: Ethernet [AppleBCM5701Ethernet]: Wake reason GIGE - bonjour - conflict resolution