MySQL error in file: /engine/modules/online.php at line 606

Error Number: 1

The Error returned was:
Can't create/write to file '/tmp/MYCcheVK' (Errcode: 28)

SQL query:

SELECT user_id, name, user_group, foto, lastdate, country, city, useragent, logged_ip, logged_proxy, location FROM dle_users WHERE lastdate < 1500807206 ORDER BY lastdate DESC LIMIT 20