Hi Leon,
it's better to add:
$CFG->preventfilelocking = true;
in your config.php file to remove locking even in other places.
BTW, you should host your Moodle instance on a file system supporting file locking: Moodle frequently uses the file system for sensitive operations like managing the pool of files and supporting MUC with the file stores, enabled by default.
HTH,
Matteo