PHP/MYSQL FULLTEXT problem

I have a PHP file that sets up a few tables and when i run the script i get
this error

"The used table type doesn't support FULLTEXT indexes"

What does it mean?

Heres the code that sets up the table

CREATE TABLE IF NOT EXISTS cms_articles (
article_id int(11) NOT NULL auto_increment,
author_id int(11) NOT NULL default '0',
is_published tinyint(1) NOT NULL default '0',
date_submitted datetime NOT NULL default '0000-00-00 00:00:00',
date_published datetime NOT NULL default '0000-00-00 00:00:00',
title varchar(255) NOT NULL default '',
body mediumtext NOT NULL,
PRIMARY KEY (article_id),
KEY IdxArticle (author_id,date_submitted),
FULLTEXT INDEX IdxText (title,body)
)

Thanks in Advance

I looked up the error on the mysql error page and it doesnt really explain anything. Anyone have an idea

im not sure but id try changing this line
title varchar(255) NOT NULL default ''
to
title mediumtext NOT NULL default '',
*shrug*

Just tried it and it didnt seem to work. This is really obthering me because i cant move on unless i work out why its doing this. Thanks for trying though.

Anyone else know what could be the problem