%1 is not a valid Win32 application for php_mysql.

Question

Im trying to set up a AMP installation on my windows 8 laptop. However, Im not being able to get PHP to talk to MySQL. When I start apache server, the following error log is generated

PHP Warning:  PHP Startup: Unable to load dynamic library 'ext\\php_mysql.dll' - %1 is not a valid Win32 application.\r\n in Unknown on line 0
PHP Warning:  PHP Startup: Unable to load dynamic library 'ext\\php_mysqli.dll' - %1 is not a valid Win32 application.\r\n in Unknown on line ..

Any idea why this could be happening?

Relevant portion of php.ini

;extension=php_bz2.dll
extension=php_curl.dll
extension=php_fileinfo.dll
extension=php_gd2.dll
;extension=php_gettext.dll
;extension=php_gmp.dll
;extension=php_intl.dll
;extension=php_imap.dll
;extension=php_interbase.dll
;extension=php_ldap.dll
;extension=php_mbstring.dll
;extension=php_exif.dll      ; Must be after mbstring as it depends on it
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_pgsql.dll
;extension=php_pspell.dll
;extension=php_shmop.dll

Answer 1

For me it helped to not load php_pdo_firebird.dll in the PHP installation, because this is being loaded in the PHP distribution.