I was also having trouble upgrading/installing Contact Form 7 on one of my sites, because it wasn't creating the database table for me.
Another site did successfully install so my resolution to the problem was in copying the database table from the one site to the other using PHPMyAdmin... here's the code I used:
CREATE TABLE
wp_contact_form_7` (
cf7_unit_id bigint(20) unsigned NOT NULL auto_increment,
title varchar(200) NOT NULL default '',
form text NOT NULL,
mail text NOT NULL,
mail_2 text NOT NULL,
messages text NOT NULL,
additional_settings text NOT NULL,
PRIMARY KEY (cf7_unit_id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
Not sure if that will work as pasted above because it's removing some of the formatting... so, here's a link to a sql with the correctly formatted code in it, open it then run the query in MySQL or via PHPMyAdmin: http://www.weblifellc.com/images/wp_contact_form_7.sql