Normally means you have no default browser set.
If you use IE
* Select ""Tools | Internet Options"" from the main menu in Explorer.
* Change to the ""Programs"" tab.
* Check the ""Internet Explorer should check to see whether it is the default browser"" option.
* Click ""OK"".
* Close all Explorer windows and restart the system. Once the system comes back up, restart Explorer.
* When the ""Would you like to make [Internet Explorer] your default browser?"" prompt appears, click ""Yes"" to make Explorer the default browser.