Strange issues on our checkout page

We're having a strange issue that I feel has to do with the cRec.asp file. It occurs on the viewcart.asp page. When you try to change the quantity and then hit the recalculate button, it returns an error saying that "Items options not available."
It gets stranger...
If you increase the quantity to a level that exceeds stock, it returns the proper stock exceeded message. So it is recalculating, it's just not returning a value to the cart.

Any ideas on this one?

Thanks in advance,
H.L.