My b2evolution Version: Not Entered

Can someone help me with this one?

MySQL error! / Lost connection to MySQL server during query(Errno=2013) / Your query: DataObjectCache::get_by_ID()SELECT * / / FROM evo_users / / WHERE user_ID = 30 in /home/nujijorg/public_html/members/inc/_core/model/db/_db.class.php at line 587

Thank's