Foren / Cotonti / Development / Chat plugin - need advice

Warning: require_once(./system/xtemplate.php) [function.require-once]: failed to open stream: No such file or directory in /home/xxx/system/functions.php on line 4926

Fatal error: require_once() [function.require]: Failed opening required './system/xtemplate.php' (include_path='.:/usr/local/lib/php') in /home/xxx/system/functions.php on line 4926

The error comes from custom.php in /lib/ folder. I copied "chat" folder straight to seditio root.