@robert leleu
This guy had a SIMILAR problem with a different variable - http://getsatisfaction.com/mozilla_messaging/topics/firefox_does_not_launch_when_a_http_link_is_clicked_in_thunderbird#reply_1050379 -
His follow-up post describes how he found out which variables thundebird was setting - http://getsatisfaction.com/mozilla_messaging/topics/firefox_does_not_launch_when_a_http_link_is_clicked_in_thunderbird#reply_1051256
Hope this helps.
@robert leleu
This guy had a SIMILAR problem with a different variable - http:// getsatisfaction .com/mozilla_ messaging/ topics/ firefox_ does_not_ launch_ when_a_ http_link_ is_clicked_ in_thunderbird# reply_1050379 -
His follow-up post describes how he found out which variables thundebird was setting - http:// getsatisfaction .com/mozilla_ messaging/ topics/ firefox_ does_not_ launch_ when_a_ http_link_ is_clicked_ in_thunderbird# reply_1051256
Hope this helps.