Does ANYONE have a clue what this means?

I had a site set up with the B&W template... It worked perfectly for weeks, then out of nowhere...The site won't load, and I can't access the admin panel.

tablesession::Store Failed
DB function failed with error number 1016
Can't open file: 'jos_session.MYI' (errno: 145) SQL=INSERT INTO `jos_session` ( `session_id`,`time`,`username`,`gid`,`guest`,`client_id` ) VALUES ( 'd87146502a569a580e972caa2b19360a','1327677951','','0','1','0' )


HELP!

If you have cpanel access an the host has provided tools to manage your mysql databases you could try a to use a repair tables command. Take a dump of the db in its current state and try it on a local system first to avoid compounding any possible issues.

{Edit}
Read this first if you would like to know more about the repair command dev.mysql.com

Thanks !