This might be a n00bish question, but I was using the SearchUI to find profitable reselling prospects. In my absentmindedness, I was at the bank when I performed the search, and noticed that the chat windows said that the auctions were queued whenever I clicked the "Purchase" button.
Upon visiting the AH, I expected to be prompted for confirmation of the auctions I had wanted to purchase. A confirmation dialog did indeed pop up, but it was for items I'm certain I had not put in the queue. I clicked cancel, expecting to see more confirmation boxes, but none appeared. Thinking the queue had been cleared, I went back into the Resale searcher wanting to find the auctions in question and purchase them, but they weren't there either.
My best guess is that your snapshot was out of date, so you added items to the queue that were, at one point, available, but were no longer available. So when you connected to the AH, we tried to find them, but they no longer existed. Searching for them also updated the snapshot for those items, so when you searched for them again, they were no longer returned as results.
The only thing I can't explain is how the confirmation dialog popped up for items you are certain you didn't put in the queue. I can't see how that would ever happen.
I'll cut you a break and write it off as a PEBKAC. ;-) I'm feeling mildly confused and not entirely confident navigating the UI (yet), so it's quite possible that I've done something unintentionally.
I'm still loving the addon, though. I've gone from just 5G to over 100G in just a few weeks - and that's with only very little effort in between tradeskill levelling and questing on my main. Who knows what I could accomplish with a dedicated banking toon. *drools*