Looks like I resolved this issue. I rebuilt the Store page and now I make it through to the sandbox.
I updated to marketpress 2.4.2 before I updated to wordpress 3.3. After upgrading to 3.3 I’m still getting the same 10400 error. I then removed my store page and the marketpress plugin. When I reinstalled the marketpress plugin the store page was not generated. When I added a new store page it remembered all my previous settings so I don’t think I really deleted it when I hit the delete button. At any rate I am still getting the same 10400 error message. Any thoughts??
