I am not able to open my email client if i click on a mailto:user@domain.com link in a webpage in Firefox 1.5.0.4 (ubuntu dapper).

Earlier I could do this but since balsa was installed and then uninstalled, things have not been the same. balsa used to start when a mailto: link was clicked on a webpage. balsa is an email client bundled with dapper.

I am using thunderbird as the default email client or wish that it becomes default again.