Time Machine Backup freezing computer
First, make sure your external drive is plugged into wall-power, not bus power.

Second, check your system.log for I/O errors.  If you find any, then one of your drives may be failing.  See my article Recover Failing Hard Drives

Third, verify both your boot drive and backup drive in Disk Utility.  Do not attempt this until you have confirmed that there are no I/O errors!  Verifying the backup drive may take a long time (twenty minutes or more) as there are a lot of hard-links to check.  Repair if needed.

If that checks out, try locating a folder named "freds mac"... unless that's the name of your boot volume.  If its not the name of your boot volume, then rename it and try the backup again.  For more Time Machine tips see my article Recommendations for System Backups: Time Machine Tips