I just uploaded a huge new batch of code. I have completely rewritten the "Add a new item" as well as the "import from plant list" features. It's now much, much more user friendly, and much more compact. Hints and information is now hidden under Question Mark icons to keep it tidy. Mouse over the icons to get tooltips that tell you what to do.
Also, the whole problem with plants not linking should now be fixed. Past plants already added aren't fixed (and can't be, but that's what happens with beta software) but any new item you add should link properly, assuming you select the plant from the list and don't change its name once you choose it.
I'd be very grateful if some folks could try adding a few new items to their swap list, and let me know if they run into any trouble.