In your provisioning template properties, what Target OS are you using. I had issues with CTOS when i only choose Windows. When i specifically chose Windows XP Pro, things worked better.
Target OS is set to Windows XP Pro, good suggestion though.
One thing I forgot to mention is that everything was working fine for over a year until we started using LANDesk AV. In order to get LANDesk AV to work for us, we had to run a number of patches on our core to fix all sorts of odd little anomalies that were slowing our clients down. After all that patching, CTOS stopped working. We don't do a great deal of provisioning during the school year (we a are a school district), but with summer approaching we need to be able to provision.
I have attached one more image that shows the task information for a provisioning task that isn't completing.
Upgrade to SP4 corrected whatever was wrong.