Listener issue

I have a couple databases running 10205 in a development environment. The production environment had not been upgraded yet, and was running 10203. The Application team wanted us to restore a couple of the databases from production onto development and keep it 10203. I still had the binaries on development so removed the 10205 databases and then recreated them as 10203 from the backup.

The listener was running out of the 10205 binaries, so I just updated the oracle home there. For some reason, the connection to the databases running 10203 is dropping with "ORA-12537: TNS:connection closed". I am pretty sure I have done this plenty of times in the past on different servers, so can't figure out what the problem is. I thought as long as the listener is running a higher version (10205), I should be fine. The listener still hands off the connection to the databases that remain 10205 without a problem. If I shutdown the 10205 listener, and startup the old 10203 listener, it hands off the connection to the newly refreshed 10203 databases without a problem.

The error showing up in the listener.log is

26-APR-2012 15:35:10 * (CONNECT_DATA=(SID=<DB_NAME>)(CID=(PROGRAM=sqlplus_at_<machine>)(HOST=machine)(USER=oracle))) * (ADDRESS=(PROTOCOL=t cp)(HOST=machine)(PORT=54980)) * establish * SID * 12518 TNS-12518: TNS:listener could not hand off client connection  TNS-12547: TNS:lost contact
  TNS-12560: TNS:protocol adapter error
   TNS-00517: Lost contact
    Solaris Error: 32: Broken pipe

I know I must be missing something, but can't think of what it is. Any ideas?

Thanks is advance

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