Sleepy Mac Pro - really sleepy!

Question

My Mac Pro just goes to sleep constantly works fine for 30min then sleeps every 2 to 5 min. So maybe my Mac Pro is just old and needs to be retired but nobody can find a solution or even a reason why this happens.
Energy Saver settings are to 'Never'
Put Hard Disks to Sleep when possible- is disabled
*Suggestions oh mac gurus?*
*Console report between sleeps as follows:*
20/10/2010 10:29:18 kernel System Sleep
20/10/2010 10:29:20 ntpd[13] sendto(17.72.255.12) (fd=26): Network is down
20/10/2010 10:29:42 kernel pci restore waited for pci8086,1a38 (15929) fail
20/10/2010 10:29:42 kernel Wake reason = EHCI
20/10/2010 10:29:42 kernel System Wake
20/10/2010 10:29:42 kernel USB (EHCI):Port 5 on bus 0xfd has remote wakeup from some device
20/10/2010 10:29:42 kernel en2: 802.11d country code set to 'X3'.
20/10/2010 10:29:42 mDNSResponder[22] Note: Frequent transitions for interface en2 (FE80:0000:0000:0000:0219:E3FF:FEDE:FF20); network traffic reduction measures in effect
20/10/2010 10:29:42 kernel en2: Supported channels 1 2 3 4 5 6 7 8 9 10 11 12 13 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140
20/10/2010 10:29:44 kernel en2: 802.11d country code set to 'IE'.
20/10/2010 10:29:44 kernel en2: Supported channels 1 2 3 4 5 6 7 8 9 10 11 12 13 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 7 8 9 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140 40 48 56 64 104 112 120 128 136 36 44 52 60 100
20/10/2010 10:29:44 kernel Auth result for: 06:26:bb:76:f7:7a MAC AUTH succeeded
20/10/2010 10:29:44 kernel AirPort: Link Up on en2
20/10/2010 10:29:45 mDNSResponder[22] Note: Frequent transitions for interface en2 (FE80:0000:0000:0000:0219:E3FF:FEDE:FF20); network traffic reduction measures in effect
20/10/2010 10:29:47 kernel Ethernet [Intel8254X]: Link down on en0 callEthernet [Intel825ed b4X]: Ly enink down on ablen1 eHarcalldware() ed by--
20/10/2010 10:29:47 kernel enableHardware() --
20/10/2010 10:30:39 com.apple.launchd[1] (org.ntp.ntpd) Unknown key: SHAuthorizationRight
20/10/2010 10:36:20 kernel AirPort: Link Down on en2
20/10/2010 10:36:20 kernel Ethernet [Intel8254X]: Link down on en0 called by disable() --
20/10/2010 10:36:20 kernel Ethernet [Intel8254X]: Link down on en1 called by disable() --
20/10/2010 10:36:20 kernel System Sleep

Answer 1

A number of sleep-related issues can appear after incremental Mac OSX updates, including the inability to properly go to sleep, problems waking from sleep, and having your display go to sleep without your Mac going to sleep. The most common culprit is Bluetooth. Try these tips to fix your sleep problems.
WAKE UP
In System Preferences>Bluetooth, uncheck Allow Bluetooth Devices To Wake This Computer. If you are using a Bluetooth mouse and keyboard, you'll have to wake your Mac by pressing the power button.
FILE CORRUPTION
Your Bluetooth preference file may be corrupt-you'll need to delete it. Turn Bluetooth off, then go to the /Users/user name/Library/Preferences folder. Look for a file called com.apple.Bluetooth.plist and trash it.The OS will create a new preference file when you enable Bluetooth again.
ENERGY SAVER
If you have issues with a Mac or display that goes to sleep at inappropriate times, you may have a problem with Energy Saver. Delete the following .plist files and restart:
-/Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist-/Users/username/Library/Preferences/com.apple.systemuiserver.plist--
(username is your name or System Administrators name)
-/Library/Preferences/SystemConfiguration/com.apple.AutoWake.plist
A restart is very important after deleting these plists. After a reboot your Mac will then generate new ones.
Some, in these forums, have had luck fixing sleep issues downloading the Combo update from this site (yours may be corrupt), not Software Update (10.6.4 Combo, etc.), disconnect all firewire + USB devices except keyboard + mouse,Repair Permissions, re-install update, Repair Permissions again + try.
You can install it right over what you have now.
DALE