Can't open JPG images taken w/ my Canon 20D

Any picture I take with my Canon EOS 20D in JPEG format for some reason, cannot be opened in my version of Photoshop CS. When I try to open a picture using File>open or by dragging, I get a "Decompress dialog that gives me options such as color depth, image size, color attributes (such as color enhance and dither), a password tab, and a Pegasus logo with the web address www.jpg.com.

When I make the selections, and click "ok" I get the following error message:

Could not complete your request because of a disk error. Tiff images open fine, and jpg images taken from other sources work fine as well. This only happens with photos taken with my Camera. I have no trouble opening these images with other photo editing, or viewing software (ACDC, olympus's Camedia, IE explorer, MS image composer, etc.).

Any ideas?

Sounds like you've installed some third party plugin that you need to remove.

I'd go with Chris' sugguestion. But does it still open .cr2 files from your D20 ok?

Pegasus PIC Press was the plug-in that was causing the problem.

I've been carrying it over from one version of photoshop to the other since 4.0. It'd been so long I forgot it was there, and then was unsure whether it was part of photoshop or not.

I deleted the plug-in, now everything works as normal.

Thanks for your help.