I have never had it happen, but have heard reports of it happening.
I suspect that the Ninja Lister does not close its data files and write them away to disk until the program terminates. If the program fails to shut down properly (e.g. power failure, reboot, etc.) then those data files could be left in an indeterminate/corrupted state.
If you made a backup on exit, you can restore from that backup from the
File menu.
You don't say what operating system you are using, so I can't be specific here. Ninja Lister stores its data files under
C:\Documents and Settings\user_account\NinjaLister for Win XP, and
C:\Users\user_account\NinjaLister for Win7. The actual listing data is in a file named
data.csv. You could look at that and see what is there (if anything).
If no joy with that, I would guess that your only option is to export your listings from eBid - via the export link at the top-left of
My eBid >
Auctions I'm Running page (
http://us.ebid.net/perl/account.cgi?mo=account-pending), and import the resultant file into Ninja Lister. This will not recover your Ninja Lister folders and auction sets though - only the listings.