Error when opening php page
When opening an orders_search.php page, in the admin section I have the following error
Warning: require_once(../../webassist/themes/theme_open.php) [function.require-once]: failed to open stream: No such file or directory in /web/htdocs/www.tessyacconciature.it/home/admin/orders_search.php on line 1
Fatal error: require_once() [function.require]: Failed opening required '../../webassist/themes/theme_open.php' (include_path='.:/php5/lib/php/')
in /web/htdocs/www.tessyacconciature.it/home/admin/orders_search.php on line 1
May you help me on how is possible fix it?