Having an issue with newly-generated numeric barcodes not scanning/reading, seemingly unlinked to product memory, in the database.

A little background: In our shoppe, we occasionally invent our own 10-digit barcodes for products, and type those numbers manually into the barcode field so that they will print out as scannable barcodes which we can affix to objects and scan at checkout. In the past we've done this for a particular line, and have had no problem after printing the initial barcoded label, scanning them back in at sales time when the item sells. We can quickly scan the code, the product is added to the sales screen, and all is well.

This weekend, however, after entering a series of new numbers in precisely the same way, I find that the newest barcode numbers aren't working-- in the sales screen, the code will scan and beep, but no product comes up associated with it. Double checking the item in the stockroom/product manager, the barcode field is still filled-- it just doesn't seem like the number has "registered" with the system.

We've tried restarting Checkout, and restarting the computer-- no help. Do you have any ideas what might be causing this problem and how we can fix it now (and in the future)? I'm not sure if our old numbers worked right away, either, so am curious if perhaps it always takes time to work.