As reported by auciker, because of a change made to improve security, login with redirection will not work for PHP 4 sites. This may also impact other areas where there is redirection, specifically polls and mailto.
To fix this:
Add this to the end of /libraries/joomla/utilities/compat/php50x.php
Code:
if (!function_exists( 'stripos' )) {
function stripos( $haystack, $needle, $offset = 0 ) {
return strpos( strtolower( $haystack ), strtolower( $needle ), $offset );
}
OR
Quote:
Upgrade to PHP 5. PHP 4 end of life was August 8, 2008. There will not be any more PHP 4 releases, even for security. (Switching PHP versions may cause problems with some 3rd Party Plugins - be sure to test thoroughly).
Source:
http://docs.joomla.org/Why_can%27t_users_login_in_version_1.5.7_with_php_4%3F