Time Machine won't complete backup to a new drive

Question

I've recently replaced my WD MyBook 1TB drive because it was beginning to fail. The current replacement is a LaCie 2TB.
I use time machine to select the drive and start a backup and it runs for a little while and then fails with no message at all. I have tried many suggestions found on this site an on the net. I deleted the partition on the disk and set it up for use with Time Machine, I have run repair on both that disk and my main hard drive. At first I thought it was the firewire connection and tried USB instead, but there appears to be something else wrong. I also tried a new WD 2TB drive, with the same results, so I don't think it is either the cable, the disk, or the port.
I tried a sudo grep backupd /var/log/system.log as someone suggested and here are the results:
Feb 1 13:35:33 ann-fords-imac com.apple.backupd[608]: Starting standard backup
Feb 1 13:35:33 ann-fords-imac com.apple.backupd[608]: Backing up to: /Volumes/backups/Backups.backupdb
Feb 1 13:35:35 ann-fords-imac com.apple.backupd[608]: Detected system migration from: /Volumes/Macintosh HD 1
Feb 1 13:35:36 ann-fords-imac com.apple.backupd[608]: No pre-backup thinning needed: 615.73 GB requested (including padding), 1.80 TB available
Feb 1 13:35:36 ann-fords-imac com.apple.backupd[608]: Waiting for index to be ready (101)
Feb 1 13:39:40 ann-fords-imac com.apple.launchd[1] (com.apple.backupd[608]): Job appears to have crashed: Segmentation fault
Feb 1 13:39:40 ann-fords-imac com.apple.ReportCrash.Root[635]: 2011-02-01 13:39:40.607 ReportCrash[635:2803] Saved crash report for backupd[608] version ??? (???) to /Library/Logs/DiagnosticReports/backupd2011-02-01-133940localhost.crash
Any suggestions on how to fix this problem? I really need to get backups working again.

Answer 1

annford wrote:
Feb 1 13:39:40 ann-fords-imac com.apple.launchd[1] (com.apple.backupd[608]): Job appears to have crashed: Segmentation fault
That's clearly a crash. There's a crash log, but we really don't need it.
A +Segmentation fault+ is some problem with the app trying to access a piece of memory it's not authorized to, or trying to change something it's not allowed to change.
You've already tried most of the things we'd start with (assuming you ran +Repair Disk+ or +Verify Disk,+ not permissions).
Your installation of OSX may be damaged. I'd suggest downloading and installing the "combo" update. That's the cleverly-named combination of all the updates to Leopard or Snow Leopard since it was first released, so installing it should fix anything that's gone wrong since then, such as with one of the normal "point" updates. Be sure to do a +Repair Permissions+ via Disk Utility (in your Applications/Utilities folder) afterwards.
I'm not real sure what version of OSX you're on -- one post says 10.6.6, the other 10.5.4.
If you're on 10.6.6, the "combo" is at: http://support.apple.com/kb/DL1349
If 10.5.8, it's at http://support.apple.com/downloads/MacOS_X_10_5_8_ComboUpdate
If an earlier version of Leopard, change the "8" at the end.