Unable to login- ORA-12560: TNS:protocol adapter error

Question

I have upgraded the oracle db to 11.1.0.7 from 11.1.0.0 . before upgrade i have stop the db and listener process.
after the upgrade, i have started the listener(mentioned the listener status below) and tried to login as a sysdba, but unable to login itself to the db. Kindly help me to login and to start the database.
Error msg :
bash-3.00$ cd $ORACLE_HOME
bash-3.00$ cd bin
bash-3.00$ sqlplus /nolog
SQLPlus: Release 11.1.0.7.0 - Production on Thu Apr 26 19:28:19 2012*
Copyright (c) 1982, 2008, Oracle.  All rights reserved.
SQL> connect sys as sysdba
Enter password:
ERROR:
ORA-12560: TNS:protocol adapter error
bash-3.00$ lsnrctl status
LSNRCTL for Solaris: Version 11.1.0.7.0 - Production on 27-APR-2012 16:30:01
Copyright (c) 1991, 2008, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1525)))
STATUS of the LISTENER
Alias LISTENER
Version TNSLSNR for Solaris: Version 11.1.0.7.0 - Production
Start Date 27-APR-2012 10:50:31
Uptime 0 days 5 hr. 39 min. 30 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u02/AIUJAPAN/oracle11g/product/11.1.0/db_1/network/ad
min/listener.ora
Listener Log File /u02/AIUJAPAN/oracle11g/diag/tnslsnr/AIGUK/listener/al
ert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1525)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=10.95.24.10)(PORT=1525)))
The listener supports no services
The command completed successfully
bash-3.00$

Answer 1

id
uid=100(oracle) gid=102(oinstall)
env | sort
CLASSPATH=:/oracle/AIG_IBM/AIG/classes12.zip:
COBDIR=/u01/opt/microfocus/cobol
HOME=/export/home/oracle
HZ=100
LD_LIBRARY_PATH=/u02/AIUJAPAN/oracle11g/product/11.1.0/db_1/lib
LOGNAME=oracle
MAIL=/var/mail/oracle
ORACLE_BASE=/u02/AIUJAPAN/oracle11g
ORACLE_HOME=/u02/AIUJAPAN/oracle11g/product/11.1.0/db_1
ORACLE_SID=AIUJAPAN
PATH=/usr/bin::/usr/local/bin:/usr/ccs/bin:/u02/AIUJAPAN/oracle11g/product/11.1.
0/db_1/bin
PWD=/export/home/oracle
SHELL=/bin/sh
SHLVL=1
TERM=ansi
TZ=Asia/Calcutta
_=/usr/bin/env
hostname
AIGUK.aig.com
cat /etc/hosts
# Internet host table
127.0.0.1 localhost
#10.95.24.73 AIGUK.aig.com
10.95.24.10 AIGUK.aig.com
10.95.24.10 AIGUK
#10.95.24.73 AIGUK
10.95.24.71 AIUNHLM
192.18.108.101 supportfiles.sun.com
#10.90.140.40 mailhost
10.90.140.55 mailhost
uname -a
SunOS AIGUK.aig.com 5.10 Generic_118833-20 sun4u sparc SUNW,Sun-Fire-V490
ifconfig
- This command is not working - saying "Command not found"
lsnrctl start
LSNRCTL for Solaris: Version 11.1.0.7.0 - Production on 04-MAY-2012 20:39:52
Copyright (c) 1991, 2008, Oracle. All rights reserved.
TNS-01106: Listener using listener name LISTENER has already been started
lsnrctl status
LSNRCTL for Solaris: Version 11.1.0.7.0 - Production on 04-MAY-2012 20:40:17
Copyright (c) 1991, 2008, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1525)))
STATUS of the LISTENER
Alias LISTENER
Version TNSLSNR for Solaris: Version 11.1.0.7.0 - Production
Start Date 27-APR-2012 10:50:31
Uptime 7 days 9 hr. 49 min. 45 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u02/AIUJAPAN/oracle11g/product/11.1.0/db_1/network/ad
min/listener.ora
Listener Log File /u02/AIUJAPAN/oracle11g/diag/tnslsnr/AIGUK/listener/al
ert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1525)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=10.95.24.10)(PORT=1525)))
The listener supports no services
The command completed successfully
lsnrctl service
LSNRCTL for Solaris: Version 11.1.0.7.0 - Production on 04-MAY-2012 20:40:46
Copyright (c) 1991, 2008, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1525)))
The listener supports no services
The command completed successfully