watchdog error

Hi guys,
recently I encountered the following error on my site www.spoedeisendehulp.org:

Warning: Table './spoedeisend1/watchdog' is marked as crashed and should be repaired query: INSERT INTO watchdog (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', '%message in %file on line %line.', 'a:4:{s:6:\"%error\";s:12:\"user warning\";s:8:\"%message\";s:575:\"Table './spoedeisend1/watchdog' is marked as crashed and should be repaired\nquery: INSERT INTO watchdog\n (uid, type, message, variables, severity, link, location, referer, hostname, timestamp)\n VALUES\n (1, 'locale', 'Parsed JavaScript file %file.', 'a:1:{s:5:\\"%file\\";s:14:\\"misc/jquery.js\\";}', 5, '', 'http://www.spoedeisendehulp.org/site/admin/settings/performance', 'http://www.spoedeisendehulp.org/site/admin/settings/performance', '2 in /home/spoedeisendehulp.org/www/htdocs/site/includes/database.mysql.inc on line 128

so what does this mean?
I think it happend when i've cleared cache data..

can someone help me out with this?

thanks in advance