Uploading images and video.

When I try to embed a photo or video from my computer I get the following:
File type not supported

We support Images (JPEG, PNG, GIF), Videos (MPEG, AVI, WMV), Presentations (PPT, PPTX) and PDF.
Technical details: id: 2500 the reason is: S3Upload(0)

Yet the file is a jpg image. What's going on?