Are you using InnoDB? The only table type that supports FULLTEXT is MyISAM.
eg
CREATE TABLE gamemech_chat (
id bigint(20) unsigned NOT NULL auto_increment,
from_userid varchar(50) NOT NULL default ’0′,
to_userid varchar(50) NOT NULL default ’0′,
text text NOT NULL,
systemtext text NOT NULL,
timestamp datetime NOT NULL default ’0000-00-00 00:00:00′,
chatroom bigint(20) NOT NULL default ’0′,
PRIMARY KEY (id),
KEY from_userid (from_userid),
FULLTEXT KEY from_userid_2 (from_userid),
KEY chatroom (chatroom),
KEY timestamp (timestamp)
) ENGINE=MyISAM;
http://sqlfiddle.com/#!2/e6635
http://stackoverflow.com/questions/20964269/1214-the-used-table-type-doesnt-support-fulltext-indexes
DROP DATABASE `phpcrawl`;
http://en.wikipedia.org/wiki/Web_crawler
http://scrapy.org/doc/