Steps to reproduce:
1. Setup a core
2. Run the 3rd party tools script
This is with rev 11366 of 1.2.x, so it has your latest fixes. Attached full output log, error is right at the end. Looks like the x264 snapshot is bad somehow? I've run clean-all and rebuilt from scratch and hit the same issue.
This does not happen on a clean install of Ubuntu Server 11.04 amd64.