问题描述：
arcgis server10.1 arcgis sde10出现下面问题
Cannot connect to database because the database client software failed to load. Be sure the
database client software is installed and configured correctly.
由于数据库客户端软件无法加载，无法连接到数据库。请确保数据库客户端软件已安装和配置正确。
找原因：
The machine where ArcGIS Server is installed is missing the 64-bit client libraries for the specific DBMS to which the connection is being made.
安装ArcGIS Server的机器缺少正在进行连接的特定DBMS的64位客户端库。
解决方法：
Install the 64-bit client libraries for the database on each ArcGIS Server machine in the site. It is important to remember that ArcGIS Server is a 64-bit application and requires a 64-bit database client, versus ArcGIS Desktop which is a 32-bit application and requires a 32-bit database client. After installing the database client, open the Administrative Tools > Services dialog and restart the ArcGIS Server service so that the new database libraries and variable changes can be detected.
在站点上的每个ArcGIS Server机器上安装数据库的64位客户端库。重要的是要记住ArcGIS Server是一个64位的应用程序，需要一个64位的数据库客户端，而ArcGIS桌面是32位的应用程序，需要32位的数据库客户端。在安装数据库客户端之后，打开管理工具>服务对话框并重新启动ArcGIS Server服务，以便可以检测到新的数据库库和变量更改。
摘自：http://support.esri.com/cn/knowledgebase/techarticles/detail/40409