Something happened in that pages that I used to be able to choose a File or
Blog Entry and the preview would appear to the right, and then I could edit the
page. Now, whenever I click on a page the "Loading preview" message appears,
but it never goes away and the page never loads. Clicking "OK" just puts me
back to where I was before hitting the "Choose" icon.

This happens for virtually every page, even the simplest HTML page.

Has anybody seen this before?