Oracle Database Discussions

I am running Oracle 10g DB on windows 2003 server, DB running in archive log mode.

1) At the DB console i see that the DB is in mount state, all the services are running.

following error at the DB console.

Agent Connection to Instance

Status Failed

Details ORA-12528: TNS:listener: all appropriate instances are blocking new connections (DBD ERROR: OCIServerAttach)

2) C:\Documents and Settings\nkhaja>sqlplus

SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jul 19 15:11:46 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Enter user-name: sys
Enter password:
ERROR:
ORA-12560: TNS:protocol adapter error


Enter user-name: sys as sysdba
Enter password:
ERROR:
ORA-12560: TNS:protocol adapter error


Enter user-name: sys as sysdba
Enter password:
ERROR:
ORA-12560: TNS:protocol adapter error

SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus

RMAN> connect target niku

target database Password:
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
ORA-12560: TNS:protocol adapter error

RMAN> exit


Recovery Manager complete.
LSNRCTL> status
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=EBSONYC02.EBSO.COM)(PORT
=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for 32-bit Windows: Version 10.2.0.1.0 - Produ
ction
Start Date 19-JUL-2007 14:05:16
Uptime 0 days 1 hr. 12 min. 55 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File C:\Apps\oracle\product\10.2.0\db_1\network\admin\liste
ner.ora
Listener Log File C:\Apps\oracle\product\10.2.0\db_1\network\log\listene
r.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=EBSONYC02.EBSO.COM)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC0ipc)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "niku" has 1 instance(s).
Instance "niku", status BLOCKED, has 1 handler(s) for this service...
Service "niku_XPT" has 1 instance(s).
Instance "niku", status BLOCKED, has 1 handler(s) for this service...
The command completed successfully
LSNRCTL>

Can you tell me what the problem is and how can i resolve this.
I think the archive destination is full, now that the DB is in open state, how can i disable archiving. am not able to connect as well.