I can't buy from the Store

I have a problem.

I can't buy things from the Store anymore. I used to be able to, and I have a few Store items, but now... It just doesn't work.

I found some things I wanted to buy, and added them to my cart. I clicked on the little cart icon up in the right corner, and go to the cart page or whatever it's called, where all the items in my cart are displayed. At the bottom right corner of the list is a big, green button that reads "Next". I click it. And from previous experiences, I know it's supposed to take me to a page that shows the total cost, and a green button that reads "Purchase" or something like that.

I click the "Next"-button, and nothing happens.

I try to right-click it, and it gives me the menu. I select "Open", and wait.

Nothing happens.

Please help me.

In case it's relevant, I'm trying to buy:

Femme Hawk Fatale - hairstyle

High Bun - hairstyle

Barrier to Entry System

It's Not Gross Public Shower Station

Stiff as a Board, Light as a Feather Dance Collection.

Thank you on beforehand for any help you can give me.

/Hedvig