Klaus Darilion Thank you vary much! You see . The OS is Red Hat Linux 7.2. So I have to install ser-0.8.10. Can it be upgraded on this OS? If it can , how to upgrade it and which version should I choose? Can I install ser-0.8.14 or other version directly without doing anything before I do this ? Thank you once again! 　　　　　　　　gg 　　　　　　　　gdut200104024532(a)163.com 　　　　　　　　　　2004-08-23