this trick worked exactly as originally posted and fixed my sibling invalid problem. thank you so much i really appreciate it!!

So my MBA has a failing HDD.

When I launch the OS, I get the Apple logo on a white screen with a grey progress bar at the bottom (the OS attempting to fix the drive) and then the machine hangs.

I'm able to use my Superdrive to access Disk Utilities from the MAC OS X DVD. The utilities tells me that I have "Invalid Sibling Link" and that it cannot repair the drive.

Using CMD-S I'm able to enter single user mode and try to fix using fsck (the hints above). Using those I get errors indicating other problems, including "invalid node structure" and DISK FULL ERROR (although I have 6 GB free according to other stats). No matter how often I try the tips above the fsck will not run because of the DISK FULL ERROR.

I purchased DiskWarrior and it's able to find the data on the drive, and rebuild a directory structure, however it cannot replace the directory structure. I can access preview and see the files. DiskWarrior tells me that I should copy those files to another drive.

However I can't copy those files to another drive because I have an Air - with only one USB port and it's occupied by the Superdrive running DiskWarrior. I've tried to switch out the drives at different points, but DiskWarrior just crashes or hangs or won't recognize the newly added drive. I've tried a USB splitter but in that scenario the computer won't read the superdrive.

Thoughts on how I solve my problem? If the drive is failing I'd like to replace it. I have a recent backup but there is newer information I'd still like to retrieve from the drive, or I'd like to try and repair and re-install the OS on this drive.