ORA-12560: TNS:protocol adapter error

I keep getting the ORA-12560 error when I try to use either SQL Plus or SVRMGRL. I have installed Oracle 8.1.5 on a Windows 2000 Advanced Server, and followed the basic generic installation.

If I explicitly specify the instance, then I can make the connection, but otherwise I can't. Do I have my listner set up correctly or am I doing something totally incorrect. For example:

With ORACLE_SID = pegas1, from a command prompt on the machine with the database, this is what I get:

C:\>sqlplus

SQL*Plus: Release 8.1.5.0.0 - Production on Mon Mar 13 15:56:14 2000

(c) Copyright 1999 Oracle Corporation. All rights reserved.

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

And yet, I can connect this way:

C:\>sqlplus sys_at_pegas1

SQL*Plus: Release 8.1.5.0.0 - Production on Mon Mar 13 15:58:57 2000

(c) Copyright 1999 Oracle Corporation. All rights reserved.

Enter password: <manager>

Connected to:
Oracle8i Enterprise Edition Release 8.1.5.0.0 - Production With the Partitioning and Java options
PL/SQL Release 8.1.5.0.0 - Production

SQL> Thanks,

Phil.
blower_at_betacanada.com Received on Mon Mar 13 2000 - 00:00:00 CST