ora-125000错误该如何解决，望高手指点，谢谢
OracleOraHome92TNSListener服务已经启动，但是用PL/SQL登录时仍出现ora-125000错误。
ora-125000错误，该怎么解决？


------解决方案--------------------
Error: ORA-12500 / TNS-12500
Text: TNS:listener failed to start a dedicated server process
-------------------------------------------
Cause: The process of starting up a dedicated server process failed.
the executable could not be found or the environment maybe set up
incorrectly.
Action: Turn on tracing at the ADMIN level and reexecute the operation.
Verify that the ORACLE Server executable is present and has execute
permissions enabled. 
Ensure that the ORACLE environment is specified correctly in
LISTENER.ORA. If error persists, contact Worldwide Customer
Support.
Explanation:
When the listener receives a connect request for a dedicated 
connection it tries to spawn and execute an Oracle process to
accept the connect request.