I use Firefox 1.0.7 and Thunderbird 1.0. Whenever I click on a mailbox link on a site or use the File>Send Link option, nothing happens. I haven’t made any changes in either program and both are cleared through the firewall (Zone Alarm Pro).
Go to Start|Settings|Control Panel|Internet Options, click the Programs tab, and make sure that Thunderbird is selected as your default E-mail program.