When I click a mailto: link, it opens evolution instead. I have nothing against evolution. it's just that I haven't found a way to share the same profile across different distros.
In any event I have the following attributes set in config:about
And thunderbird is installed
[root:~#] locate thunderbird | grep bin
[root:~#] ls -la /usr/bin/thunderbird
-rwxr-xr-x 1 root root 2260 2008-02-27 01:50 /usr/bin/thunderbird
Using /usr/bin/thunderbird from the command line works.
I am currently using KDE and have KDE set to launch /usr/bin/thunderbird as the default mail app.