Well here is how to fix it! Click on your item in your set to visit the Polyvore product page, if it says "sold out" click the Zazzle link that says "visit Zazzle anyway". This takes you to the Zazzle product page, wait for the page to fully load and then reclip the item. Be sure to choose the same size clip you chose for the original (large or small) if it gives you an option. Done! Now go back to your Polyvore product page and it should no longer say sold out. If it still says sold out, try refreshing the page and that should fix it. It is a hassle and extra work but I think it is worth it to reclip all the products I am trying to promote on Polyvore from time to time in order to keep from losing a sale I might have gotten. I also have a notice at the top of my Polyvore profile that says "Polyvore flaw> Sold out often wrong! Go there anyway!" but not everybody is going to see my profile page to read this notice, so I am working on re-clipping as many items as possible which is a real challenge given the limited amount of time I have to spend working on my online sites.
I hope this helps some of you who have been on the verge of giving up on Polyvore as a way to promote because I really think there is good potential to reach buyers on Polyvore if we can just use it wisely!