When you save a document, avoid using spaces and special characters in file and folder names. In particular, do not use special characters (such as é, ç, or ¥) or punctuation (such as colons, slashes, or periods) in the names of files you intend to put on a remote server; many servers change these characters during upload, which will cause any links to the files to break. Also, do not begin a filename with a numeral.

Keep the file name under 8 lettters and use lowercase.

To save a document:

1. Choose File > Save.
2. In the dialog box that appears, navigate to the folder where you want to save the file.
3. In the File Name text field, type a name for the file eg. about.html
4. Click Save to save the file.
   

Remember: Your front page should be named index.html

Source: Dreamweaver MX Help