I had an identical problem, and I discovered that by opening up a terminal session and doing an ls -lo (long output, display "file flags") that the un-deletable files had a flag of "uchg" (unmutable) meaning they could not be changed or deleted without first clearing the flag.

To remedy this, use the chflags command with the "nouchg" parameter to clear the flag. You may have to be root to execute the command. You should then be able to remove (rm) the offending files easily.

Check out the chflags man page for additional details.

The command is :
chflags -R nouchg *

I had the "invalid sibling link" and ran it through DiskWarrior. I got a bunch of files (aliases to no known file) that would not delete. As root (logged in, not su) the "Locked" box was checked and I couldn't change it.

I finally booted to 9 just to unlock and trash them.

Next time I'll try this. Thanks!