Oracle 8.1.7: TNS-12541: TNS No Listener

Question

The OracleHOME_SVRTNSListener service is running. The listener.log file correctly states this fact. When I connect from SQL*Plus Worksheet (username@dbname/pw) it do connects me. Connecting from Dev 6i forms is also ok. Accessing from PHP script also works well. However, all of the below cases give this error "TNS-12541: TNS No Listener".
a. Connecting from SQL*Plus.
b. exp/imp utility program. (if i misspell connect string, the error is as expected i.e. TNS protocol adapter error. For correct connect string as defined in TNSNames.ora, the above error appears).
c. Running lsnrctl.exe and giving 'stop' command also gives the same error. However, 'start' says that the aformentioned service is already running and then gives the same error message.
Plz Note:
The last thing I did after which this problem got in was to run Database Configratio Assistant to make script of a 3rd DB on my system (Intel P-IV, Win 2K A server) and then run the generated batch file.
Also note that the newly created DB is working fine and accessable as well i.e. from sql plus worksheet and php scripts
The sqlnet.log file does record the error but tells the same story "error 12541 - TNS No Listener".
There is an interesting situation to tell. I have 8i on another machine as well (call it B). when I configure and connect using B's exp/imp utility or sql*plus or anything to A (the problamatic oracle machine), it works fine i.e.
exp [email protected]
works exactly fine. It connects to mydb on machine A using system account and starts exporting. But Why doesn't this mechanism works on machine A itsself???

Answer 1

Here is the output of few commands (all given on server machine)
Listener.ora
# LISTENER.ORA Network Configuration File: C:\oracle\orasvr81\network\admin\listener.ora
# Generated by Oracle configuration tools.
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = billingserver)(PORT = 1521))
(DESCRIPTION =
(PROTOCOL_STACK =
(PRESENTATION = GIOP)
(SESSION = RAW)
(ADDRESS = (PROTOCOL = TCP)(HOST = billingserver)(PORT = 2481))
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = C:\oracle\orasvr81)
(PROGRAM = extproc)
(SID_DESC =
(GLOBAL_DBNAME = billing)
(ORACLE_HOME = C:\oracle\orasvr81)
(SID_NAME = mydb)
tnsnames.ora
# TNSNAMES.ORA Network Configuration File: C:\oracle\orasvr81\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
EXTPROC_CONNECTION_DATA.NTR1.COM =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
mydb =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = billingserver)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = mydb)
tnsping mydb
TNS Ping Utility for 32-bit Windows: Version 8.1.7.0.0 - Production on 20-OCT-2004 09:18:01
(c) Copyright 1997 Oracle Corporation. All rights reserved.
Attempting to contact (ADDRESS=(PROTOCOL=TCP)(HOST=billingserver)(PORT=1521))
TNS-12541: TNS:no listener
lsnrctl stop listener
LSNRCTL for 32-bit Windows: Version 8.1.7.0.0 - Production on 20-OCT-2004 09:27:42
(c) Copyright 1998 Oracle Corporation. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC0)))
The command completed successfully
lsnrctl start listener
---------------------------------------------------LSNRCTL for 32-bit Windows: Version 8.1.7.0.0 - Production on 20-OCT-2004 09:27:53
(c) Copyright 1998 Oracle Corporation. All rights reserved.
Starting tnslsnr: please wait...
TNSLSNR for 32-bit Windows: Version 8.1.7.0.0 - Production
System parameter file is C:\oracle\orasvr81\network\admin\listener.ora
Log messages written to C:\oracle\orasvr81\network\log\listener.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC0ipc)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=billingserver.ntr1.com)(PORT=1521)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=billingserver.ntr1.com)(PORT=2481))(PROTOCOL_STACK=(PRESEN TATION=GIOP)(SESSION=RAW)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC0)))
STATUS of the LISTENER
Alias listener
Version TNSLSNR for 32-bit Windows: Version 8.1.7.0.0 - Production
Start Date 20-OCT-2004 09:27:53
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security OFF
SNMP OFF
Listener Parameter File C:\oracle\orasvr81\network\admin\listener.ora
Listener Log File C:\oracle\orasvr81\network\log\listener.log
Services Summary...
PLSExtProc          has 1 service handler(s)
mydb          has 1 service handler(s)
The command completed successfully
P.N. The tnsnames.ora file is the same on server (A) as on client machine (B). Everthing (imp/exp/sql plus/tnsping mydb) works fine from B, non of them works from machine A , don't know why???