Ran into this error a couple of times before when adding content to a CCK email field in MySQL 5.0.27: user warning: Field 'field_email_email' doesn't have a default value query:
It seems the email field is initially set up to not allow null values. To fix this check out this patch or just update the field in phpMyAdmin: ALTER TABLE `table_name` CHANGE `field_email_email` `field_email_email` VARCHAR( 255 ) CHARACTER SET utf8 COLLATE utf8_general_ci NULL