Please upgrade to apt version 0.6.46.4ubuntu6 and see if it still does it. onc eyou remove the bin files from /var/cache/apt/ leave them deleted and it should work fine. the .bin files were getting corrupted but this issue has been fix in feisty.
-- apt segmentation faults (core dump) in feisty https://launchpad.net/bugs/72475 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
