当我尝试在 ubuntu 服务器 12.04 中安装 fastcgi 时，出现以下错误：
sudo apt-get install libapache2-mod-fastcgi
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package libapache2-mod-fastcgi is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'libapache2-mod-fastcgi' has no installation candidate
有什么解决办法吗？