I downloaded many free motion backgrounds and stills today from your media store.

Several of the images in their respective media folders had a small triangle w/ an exclamation point in the center after I downloaded them.

The media do not show up in the preview or live pane when previewed in Easyworship. The screen stays black.

Does that mean the media are no longer available in your store?

This means that the software is running into a problem loading the file.
You may try redownloading it. It should still be in the store. Let me know if you can't find it to download it.