Erro de conexão em Windows 7

Ola Turma.

Fiz a instalação do ORACLE 10g Expresss num W7. Na instalação não tive problemas, tudo correu normalmente. Porem quando eu tento acessar me deparo com as seguintes dificuldades.

via APEX -> Não encontra a página.

Via SQLDEVELOPER -> erro : ORA12505.

Via SQL Command , utilizando CONN . -> ORA-12638.

quando eu tento pingar o TNS ei tenho essa resposta :

tnsping XE

TNS Ping Utility for 32-bit Windows: Version 10.2.0.1.0 - Production on 15-MAR-2013 09:04:18

Copyright (c) 1997, 2005, Oracle. All rights reserved.

Arquivos de parâmetros usados:
C:\oraclexe\app\oracle\product\10.2.0\server\network\admin\sqlnet.ora

Usado o adaptador TNSNAMES para resolver o apelido
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = LOCALHOST)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = XE)))
OK (10 ms)

listener.ora

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 = LOCALHOST)(PORT = 1521))
)
)

DEFAULT_SERVICE_LISTENER = (XE)

tnsnames.ora

XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = LOCALHOST)(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)
)
)

achei algo estranho no arquivo CSS, mas não sei identificar o que!

[ OCRUTL][2796]u_set_gbl_comp_error: Parameter was NULL
[ OCRUTL][2796]u_set_gbl_comp_error: Parameter was NULL
2013-03-15 08:04:22.196: [ OCRRAW][2796]proprinit: Could not open raw device
2013-03-15 08:04:22.196: [ default][2796]a_init:7!: Backend init unsuccessful : [33]
[ OCRUTL][2796]u_set_ocr_error: Parameter was NULL
2013-03-15 08:04:22.196: [ CSSCLNT][2796]clsssinit: error(33 ) in OCR initialization

Alguém pode me ajudar???