Creating Disk Image Freezes

I'm attempting to do a full backup of my boot drive to an external hard drive using Disk Utility to create a disk image. For some reason, it always gets to a certain point, and then locks up. This morning when I came into the office, it was locked up on the task "Adding Resources". I've successfully created disk images of other workstations on this hard drive, but for some reason have been unsuccessful with my main workstation.

Anyone have any thoughts as to why this is happening? Does Carbon Copy Cloner create a full disk image just as good as Disk Utility? I find it odd that I don't have to unmount the disk that CCC is creating a disk image from. Thoughts?

Thanks

Dave