PHP OCI8 Unable to load. Not a valid win32 application

I tried so many times changed the php.ini into this :

extension=php_mysql.dll

extension=php_mysqli.dll

extension=php_oci8.dll ; Use with Oracle 10gR2 Instant Client

extension=php_oci8_11g.dll ; Use with Oracle 11gR2 Instant Client

;extension=php_openssl.dll

;extension=php_pdo_firebird.dll

extension=php_pdo_mysql.dll

extension=php_pdo_oci.dll

;extension=php_pdo_odbc.dll

;extension=php_pdo_pgsql.dll

extension=php_pdo_sqlite.dll

;extension=php_pdo_sqlite_external.dll

;extension=php_pgsql.dll

;extension=php_pspell.dll

;extension=php_shmop.dll

but when I restart the Apache in XAMPP , this show up as a warning :

PHP Startup : Unable to load dynamic library ‘C:\xampp\php\ext\php_oci8.dll’ – %1 is not a valid Win32 application.

PHP Startup : Unable to load dynamic library ‘C:\xampp\php\ext\php_oci8_11g.dll’ – %1 is not a valid Win32 application.

PHP Startup : Unable to load dynamic library ‘C:\xampp\php\ext\php_pdo_oci.dll’ – %1 is not a valid Win32 application.

i've checked and those are exist in my php\ext

For information i used "Windows Version: Windows 7 Home Basic SP1 64-bit"
"XAMPP Version: 1.8.1" and "Control Panel Version: 3.1.0 3.1.0" and "[PHP: 5.4.7]" and I'm using OracleXE11.