Thanks for the quick reply! Yes, it only happens when adding a new PDF item; there is no problem with pictures. If adding to an existing item, it saves with no problem. I've worked around it by closing and saving the item with just the name ("APPLY" doesn't seem to be enough), then opening and finishing the details with the attachment - that way I don't feel I've wasted too much energy.
Also, I would like to let you know how much I appreciate your software. I'm one of those who was left high and dry from Home Inventory Pro, and have been copying items one-by-one into this new software. Thank goodness for you! (Please don't leave us!!!!)