Oracle Wallet Setup ORA-12578

I am having trouble setting up the Oracle Wallet on a new box connecting to a new database. I have added the following lines to my SQLNET.ORA: SQLNET.WALLET_OVERRIDE = TRUE WALLET_LOCATION = (SOURCE=(METHOD=FILE)(METHOD_DATA=(DIRECTORY=c:\oracle\Wallet)) The wallet is created without error, the credentials added, and I can list the credentials back from the wallet without a problem, but when I go to use them I get an ORA-12578 as follows: C:\oracle\Wallet>sqlplus /@MYDB SQL*Plus: Release 11.2.0.1.0 Production on Mon Oct 31 16:57:53 2011 Copyright (c) 1982, 2010, Oracle. All rights reserved. ERROR: ORA-12578: TNS:wallet open failed I am on a 64 bit box using the 32 bit 11.2 client to connect to an 64 bit 11.2 database. Logging in without the wallet works fine. The error message indicates that I should turn tracing on. I have done so, but don't see anything obvious. Does anyone have a suggestion before I contact Oracle support?