ORA-12560: TNS:protocol adapter error
What causes this error?
An ORA-12560 error message indicates that there is a problem at the protocol adapter level. That is, SQL*Net and the Interchange are functioning correctly, but there is something wrong with the protocol adapter that underlies them.
How to fix it
Check addresses used for proper protocol specification. Before reporting this error, look at the error stack and check for lower level transport errors. For further details, turn on tracing and re-execute the operation. Turn off tracing when the operation is complete or you will use a lot of disk space. The trace file will have details of the problem.
You may get this error running Oracle 8.1.6 under Win2000 when you try to log in using 'svrmgrl'. You can normally connect using SQL*Plus or any other product, svrmgrl is going to be discontinued.