item quantity discount not found

I have an issue I hope someone can help me with. I had created a mix/match
discount scheme for a group of items that I was overstocked with. Now that
the items are at the levels I wanted them to be I didn't want them
discounted anymore. Since you can't remove a bunch of items from discount at
once I decided to delete the discount scheme. It seemed to work OK because
when I looked into the item properties discount tab everything had no
discount selected. However, when we sell one of these items it comes up with
"warning 907 - the item quantity discount was not found in the database"
even though it shows no discount selected in the discount tab. If I go into
the discount tab and select a discount and enter, then go back into the
discount tab and select no discount, it fixes it. I'm assuming there's some
sort of flag set to true when you select a discount, and it stays that way
until you select no discount. does anyone know of a way I can fix this
without having to go into each item manually? Any help would be greatly
appreciated.
Craig