Username retrieval failed in 10g XE. Help!! (Thanks!)

Question

Hi all -
Any help would be sincerely appreciated! (although who would write "all help would be looked upon poorly" ???)
Anyway, I installed 10g XE on Windows XP Pro
Installation was successful, and I AM able to launch the GUI Administrator (i.e., the one that the "Getting Started" doc talks about).
I'm able to query tables, create users, all that great stuff.
However, when I go to Start -> Programs -> Oracle Database 10g Express Edition -> Run SQL Command Line,
I am unsuccessful at being able to Connect.
I launch the Run SQL Command Line, type in "connect username_i_created/password@xe" and I get the error "ORA-12631: Username retrieval failed"
This username DOES exist and I can see and query when I go through the GUI.
Any thoughts or suggestions?
Thanks Again!!
R-

Answer 1

Thank you all, for your suggestions! Unfortunately, I'm still having problems.
Ultimately, I have another software application that is meant to connect to my Oracle database. That's failing with the same ORA-12631 error as I mentioned.
I'm still unable to log in, even directly, via SQL*Plus.
Through my Command window:
C:\>echo %ORACLE_SID%
XE
C:\>echo %ORACLE_HOME%
C:\oraclexe\app\oracle\product\10.2.0\server
C:\sqlplus username/password
SQL*Plus: Release 10.2.0.1.0 - Production on Fri Jul 15 10:51:29 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
ERROR:
ORA-12631: Username retrieval failed
and my sqlnet.ora file is posted here:
# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.
SQLNET.AUTHENTICATION_SERVICES = (NTS)
my tnsnames.ora file:
XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = full computer name from My Computer->Properties->Computer Name)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
ORACLR_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
(CONNECT_DATA =
(SID = CLRExtProc)
(PRESENTATION = RO)
my listner.ora file:
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = C:\oraclexe\app\oracle\product\10.2.0\server)
(PROGRAM = extproc)
(SID_DESC =
(SID_NAME = CLRExtProc)
(ORACLE_HOME = C:\oraclexe\app\oracle\product\10.2.0\server)
(PROGRAM = extproc)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
(ADDRESS = (PROTOCOL = TCP)(HOST = full computer name from My Computer->Properties->Computer Name)(PORT = 1521))
DEFAULT_SERVICE_LISTENER = (XE)