Happy New Year Everyone!

I have Mac OS 10.4.3 installed. I'm using Firefox 1.5.

I've noticed that when ever I open Firefox I get these files called bookmarks.html and bookmarks-2006-01-01.html. The files are created in a folder located in:
'/Users/youruserfolder/Library/Application Support/Firefox/Profiles/8wuhgjhv.default'

Each time I open Firefox the bookmark files are created again. For example, bookmarks-1.html, bookmarks-2.html etc. If I open Firefox 5 times 5 bookmark.html files are created. I deleted over 45 bookmark.html files yesterday and its getting kind of annoying. How do I stop these files from being created? Thanks.