Are you using the latest client? Do you have multiple (copied) wallets? Can you write the exact text on the line 0/unconfirmed or 0/.... ?
I am using Bitcoin version 0.3.22-beta
Does version matter?
I have two copies, one in a computer, one in a flash drive. Both encrypted with TruCrypt.
The exact text is:
0/unconfirmed 7/19/2011 22:25
Well, I may have had a very different use case, but I noticed a difference between an older client and 0.3.24. In my case I copied the wallet. I probably send coins from walletA and then closed the client and opened the copied walletB and sent coins again. In client 0.3.24, I saw two transactions. One with 0/unconfirmed and another with 3000+ confirmations. It looked weird, but it was clear that the first transaction never made it into the block chain.