Oracle连接问题tnsname

昨天建的数据库，用PL/SQL登陆OK，没有问题。
结果今天上班来一看，连接的时候报：ORA-12154：无法解析指定的连接标示符。
我用sqlplus登陆却可以登陆上去，不知道是什么原因，请各位大侠帮忙看一下。
--------------
listener配置：
# listener.ora Network Configuration File: C:\oracle\product\10.2.0\db_2\network\admin\listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\product\10.2.0\db_2)
      (PROGRAM = extproc)
    )
      (SID_DESC =
       (GLOBAL_DBNAME = ORCL)
       (ORACLE_HOME = ORCL)
       (SID_NAME = ORCL)
       (SERVICE_NAME = ORCL)
      )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 98eacd934002461)(PORT = 1521))
    )
  )
---------------
tnsname配置：
# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\db_2\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST = (PROTOCOL = TCP)(HOST = 98eacd934002461)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

--------------------------
帮忙看一下为什么用PL/SQL连接不上，谢谢

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