我得到“缺少这些必需的宝石”，但安装了宝石

since I updated ruby using Mac Ports (on Leopard) I have got several problems and I also had to reinstall gems. Now when I run Mongrel I keep getting the error "Missing these required gems" followed by the list of gems that I required in environment.rb but that gems seems to be correctly installed as I see running since I updated ruby using Mac Ports (on Leopar