In other words, this:
LOAD DATA INFILE "administrations/employee/salary/upload/marcsv.csv" INTO TABLE employee FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n';
looks like a SQL query. PHP is not SQL, so you can't just throw a SQL query into a PHP script and expect PHP to know what to do with it.
Furthermore, note that the entire [man]mysql[/man] plugin is quite outdated and has been deprecated in favor of [man]MySQLi[/man] (or [man]PDO[/man]). See the PHP manual page [man]mysqlinfo.api.choosing[/man] for more info about choosing which API to use.