The “function.unserialize” error occurs while installing Kayako or any other 3rd party application when the “magic_quotes_gpc” parameter is enabled.
By default the value
of “magic_quotes_gpc” is On in the server side PHP configuration and thus you receive the following error message:
[Notice]: unserialize() [function.unserialize]: Error at offset 5 of 41 bytes (includes/functions.php:82) UNSERIALIZE FAILED: [Warning]: Cannot modify header information - headers already sent by (Cookie/class.SWIFT_Cookie.php:157)
The “magic_quotes_gpc” can be disabled server wide ( in /etc/php.ini), however, if you want to keep it enabled server side, it can be disabled for the specific account as well either by using .htaccess (if server is non-SuPHP) i.e. placing the following line
php_value magic_quotes_gpc 0
OR by copying the server side php.ini file under the specific account or directory the application is downloaded
cp /etc/php.ini /home/user/public_html/
and turn off magic_quotes_gpc in new php.ini file (in case SuPHP is enabled).