منتدى استراحات زايد - Forum the forum is down

i could not open my forum today and i got this message:

Warning: mysql_query() [function.mysql-query]: Unable to save result set in [path]/includes/class_core.php on line 412

and then :

Database error in vBulletin 4.0.2:

Invalid SQL:

SELECT forum.forumid, forum.lastpost, forum.lastposter, forum.lastposterid, forum.lastthread, forum.lastthreadid, forum.lasticonid, forum.threadcount, forum.replycount, forum.lastpostid, forum.lastprefixid, user.usergroupid, user.homepage, user.options AS useroptions, IF(userlist.friend = 'yes', 1, 0) AS isfriend

FROM forum AS forum

LEFT JOIN user AS user ON (user.userid = forum.lastposterid)
LEFT JOIN userlist AS userlist ON (userlist.relationid = user.userid AND userlist.type = 'buddy' AND userlist.userid = 1);

MySQL Error : Table 'user' is marked as crashed and should be repaired
Error Number : 1194
Request Date : Tuesday, June 22nd 2010 @ 04:36:18 AM
Error Date : Tuesday, June 22nd 2010 @ 04:36:18 AM
Script : http://hanalalhan.com/forum/forum.php
Referrer :
IP Address : *****
Username : *****
Classname : vB_Database
MySQL Version : 5.1.47-community-log

any help please ? i'm still beginner by the way ..