【求助】Ubuntu11.04安装Firefox6.0问题！

[root@localhost ~]# cd /home/new/Desktop

[root@localhost Desktop]# tar jxvf Firefox-latest.tar.bz2

[root@localhost Desktop]# cd /home/new/Desktop/firefox

[root@localhost firefox]#./configure --prefix=/opt/firefox

出现的问题是：./configure: 没有那个文件或目录
请问到底该怎么安装这个从官网下载的firefox6.0，加压出的文件里的README.txt啥也没有说明怎么安装啊。
从网上查要我在系统firefox没有running的状态下执行：[root@localhost firefox]#./firefox
可是不行，出现下面的问题：

root@ubuntu:/home/yuxianghao/下载/firefox# ./firefox

(firefox-bin:25850): GnomeUI-WARNING **: While connecting to session manager:
None of the authentication protocols specified are supported.
**
GLib-GIO:ERROR:/build/buildd/glib2.0-2.28.6/./gio/gdbusconnection.c:2279:initable_init: assertion failed: (connection->initialization_error == NULL)
root@ubuntu:/home/yuxianghao/下载/firefox#
(crashreporter:25909): GnomeUI-WARNING **: While connecting to session manager:
None of the authentication protocols specified are supported.
**
GLib-GIO:ERROR:/build/buildd/glib2.0-2.28.6/./gio/gdbusconnection.c:2279:initable_init: assertion failed: (connection->initialization_error == NULL)

请问该如何安装 Firefox-latest.tar.bz2