On many of our servers xcache is use as part of the php caching mechanism. If you are encountering a script having difficulty with it you may disable it via an .htaccess file in the scripts folder and the following lines:
php_flag xcache.cacher Off
php_flag xcache.size 0
php_flag xcache.stat Off
php_value xcache.enable Off
The .htaccess file is a text file that contains configuration directives for Apache.
You can use the .htaccess file to disable XCache for a specific domain.