I was able to get to the page where it denied my transfer because I still have items for sale, and still in a FC (just wanted to check it out while at work).

Note if people haven't figured it out yet: When you select your destination world, you need to click on Confirm beside it. This will show you available characters on that world already, if applicable. Then select your current world, and click on Confirm. I did get a few errors trying this, but after the 3rd or so attempt, I finally got through these parts.

Until I clicked on Confirm for my destination world, no characters were showing up in my current world list.

Hopefully that helps some people (like Jahunga), because in SE fashion, they like to make things as complicated as possible. Chances are, you're still going to get a ton of errors, but I can confirm that the service is working... it's just sketchy as hell right now.