Ok I got the thing to tweet to twitter, but it still says

URL was not shortened for Twitter: www.opalessenceshop.com was used instead. Reason: INVALID_LOGIN

I have reset my bit.ly API key, so I know that's right... I think my username is OpalEssenceShop... at the top of the page it says, for example, "@OpalEssenceShop Account Settings" (at https://bitly.com/a/account) so what is going wrong?

And treefrog, how did you get it to tweet on update with an option to not tweet? I'd really like that, because a lot of times I add products when I have time, ahead of when they're actually ready to sell, then make the product and go in and change the status of the product or change the quantity from 0 to 5 or whatever--and I'd like to tweet it *then*...