Getting this error on Centos 6 with PHP 5.3 when just running "php -v"
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/module.so' - /usr/lib64/php/modules/module.so: cannot open shared object file: No such file or directory in Unknown on line 0
PHP Warning: Cannot load module 'XCache' because conflicting module 'apc' is already loaded in Unknown on line 0
This is caused by php-mcrypt and usually means your OS doesn't have mcrypt installed and Centos by default doesn't seem to have it.
The easiest thing to do if you aren't using it is to remove it:
yum remove php-mcrypt
You could also edit /etc/php.d/mcrypt.ini and comment the line out and add the module back when and if you get it.