@meredithbead, you have been listing items last few days, did you have any problem with the “product category” box when listing items, either by Duplicate or Create New? Also, are you able to Edit published listing (make some change then publish again)?
Just wondering if you, or anybody else here, are having any of the problem described above by Wade or me. Try to figure out if this is a wide spread problem or is just somehow isolated to some sellers.