That means other people can't see that one either. And people can't buy what they can't see.
Hopefully these screen shots will help towards improving the auction house.
Here is the proof that you can search for your own items in case there was confusion over being able to do so.
(copy and paste links into browser without the bracketed material)
As the timer on the auction ended, I sighed in relief. I thought "Now I can re-list it and then sell it this time."
I'm starting to think the problem is linked to the item itself. Perhaps the item ID isn't being recognized by the auction house or something.