Listener problem with Oracle 10gR2 after upgrade to 10.2.0.4

Symptom Brief Description: TNS errors 12437, 12560, and Solaris Illegal Seek on listener startup.

We ran into this issue starting an instance after upgrading from 10.2.0.1 to 10.2.0.4 (on Solaris)

Symptom:
On attempting to start the listener the startup fails with the error below

TNS-12537: TNS:connection closed
TNS-12560: TNS:protocol adapter error
TNS-00507: Connection closed
Solaris Error: 29: Illegal seek

Things that may solve this problem in other cases, but didn't work for us:

• Metalink: 315720.1 -- insufficient permissions to /etc/hosts/ file, or missing localhost entry
• Metalink: 555609.1 -- excellent article with troubleshooting steps for this error
• Metalink: 3168651 -- Manually relink
  

The Problem:
In this case, the LD_LIBRARY path contained a reference to a path containing InstantClient

What Fixed it for Us:
Reset the LD_LIBRARY path to the correct path and the listener started without issue.