php error happened

Technical information
Error type2
Error descriptionrequire_once(include/export_functions.php): failed to open stream: No such file or directory
URLnadac.com/top_ten/Top_Ten_by_Class_export.php?all=1&format=word
Error file/home/nadac1/public_html/top_ten/Top_Ten_by_Class_export.php
Error line65
SQL query

More info