sqlplus不得不远程登陆

sqlplus只能远程登陆
本机实例监听都启动了,PL/SQL中SCOTT及其他账户均可登陆，sqlplus中就不行：

SQL code

C:\Users\e>sqlplus/nologSQL*Plus: Release 10.2.0.3.0 - Production on 星期三 8月 1 12:49:03 2012Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.SQL> connect scott输入口令:ERROR:ORA-12560: TNS: 协议适配器错误

为什么改为远程登陆就可以了呢，原来不这样的呀 

SQL code

C:\Users\e>sqlplus scott/scott@localhost:1521/orclSQL*Plus: Release 10.2.0.3.0 - Production on 星期三 8月 1 12:50:14 2012Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.连接到:Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - ProductionWith the Partitioning, OLAP and Data Mining options

ORA文件：

XML code

ORCL =  (DESCRIPTION =    (ADDRESS = (PROTOCOL = TCP)(HOST = e-PC)(PORT = 1521))    (CONNECT_DATA =      (SERVER = DEDICATED)      (SERVICE_NAME = orcl)    )  )

[解决办法]
此问题可能是oracle_sid没有设置或者设置错误导致的.
解决办法:
cmd命令行上:
C:\> set ORACLE_SID=instance名字