Really all you need to do is put your favicon.ico in the root of your installation and it should automatically cascade to every page in every folder within the installation root. Modern browsers are designed to do this for us. There is really no need to define the favicon on every page.
Like this...
http://www.yoursite.com/your_ost_install/favicon.ico(http://www.yoursite.com/your_ost_install/favicon.ico)
although this method is discouraged (due to out of date W3C standards), it is the defacto "out-of-the-box" solution when using a modern browser.
If after doing this, it still doesn't work, perhaps a browser upgrade is in order.
