系统管理员登录在windows系统中以另一个用户ibm启动posgresql数据库的办法

在cmd窗口输入
C:/>runas /user:ibm cmd
输入 ibm 的密码:
试图将 cmd 作为用户 "IBMLT/ibm" 启动...
然后在新开的窗口中
C:/pgsql/lib>../bin/pg_ctl start -D d:/pgdata
启动 postmaster

C:/pgsql/lib>LOG:  database system was shut down at 2006-02-26 21:42:29 中国标准
时间
LOG:  checkpoint record is at 0/2056A888
LOG:  redo record is at 0/2056A888; undo record is at 0/0; shutdown TRUE
LOG:  next transaction ID: 422077; next OID: 16987
LOG:  next MultiXactId: 1; next MultiXactOffset: 0
LOG:  database system is ready
LOG:  transaction ID wrap limit is 2147484146, limited by database "postgres"
接着在原来的窗口中
C:/pgsql/lib>../bin/psql  -U ibm -d postgres
Welcome to psql 8.1.2, the PostgreSQL interactive terminal.

Type:  /copyright for distribution terms
       /h for help with SQL commands
       /? for help with psql commands
       /g or terminate with semicolon to execute query
       /q to quit

postgres=#
postgres=# /l
           数据库列表
   名字    | 所有者 |   编码
-----------+--------+-----------
 lt_pgdb   | ibm    | SQL_ASCII
 postgres  | ibm    | SQL_ASCII
 template0 | ibm    | SQL_ASCII
 template1 | ibm    | SQL_ASCII
(4 行)

疑问：为什么在C:/pgsql/bin>psql  -U ibm -d postgres报告没有找到libpq.dll,因此这个应用程序未能启动
我是从no_install版本安装的