One thing for sure, the file name and your link to that file are NOT the same.

The simple insurance for making a Web page function properly is to (1) make it work on your computer or floppy then (2) upload every file EXACTLY as they are on your computer. This means that all files have to be exactly is the same "relative" location, i.e. in the same folders. If you add a graphic to a Web page you must not only upload the updated Web page but the graphic file as well. My best tip is to "avoid typing" whenever possible, i.e. when linking always browse to the file and select it or "copy 'n paste" links. (Typos are the origin of most "file not found" errors.) If you continue to have problems, come to my office hours or during class period.