To fix the error you are getting you need to restart your MYSQL server.
for example, on Fedora Core 4 (red hat) go to the command link or shell and type the following:

/etc/init.d/mysqld restart

Thats it, reload the page that was giving you the error below and it should go away

If you have hosting by a company who does shared web hosting, then you need to call them and advise that you are getting this error message.

DB Error: unknown error
SELECT distinct(session_id) FROM mod_visitors_hit WHERE timestamp>date_sub(now(), interval 5 minute) ORDER BY user DESC, ip [nativecode=1030 ** Got error -1 from table handler]
Warning: Unknown(): write failed: No space left on device (28) in Unknown on line 0

Warning: Unknown(): Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0