PDO exception error when applying for a job

This is a serious bug,it doens't allow me to create a new blogpost (using the core blog module) and probably and other functions in the site.
Anyone help me?
thanks

I finally solved this,I did this

-First enabled the Message module and then the Job application module
-I rebuild permissions after enabling the Job application module

That's it

Using the simpletest.me service it works fine but using it locally it still gives a PDO exception error.Thoughts?

Anyone help me on this?Apache shows no information.
thanks

This is what I take when I try to enable the Message module:

PDOException: SQLSTATE[42000]: Syntax error or access violation: 1171 All parts of a PRIMARY KEY must be NOT NULL; if you need NULL in a key, use UNIQUE instead: CREATE TABLE {message} ( `mid` INT unsigned auto_increment DEFAULT NULL COMMENT 'The Unique ID of the message.', `type` VARCHAR(255) NOT NULL DEFAULT '' COMMENT 'Reference to a message a type.', `arguments` TEXT DEFAULT NULL COMMENT 'Serialized array with the arguments', `uid` INT unsigned DEFAULT NULL COMMENT 'The user ID of the acting user.', `timestamp` INT unsigned NOT NULL COMMENT 'When the message instance was recorded.', `language` VARCHAR(12) NOT NULL DEFAULT '' COMMENT 'The languages.language of this message.', PRIMARY KEY (`mid`), INDEX `type_index` (`type`), INDEX `timestamp` (`timestamp`) ) ENGINE = InnoDB DEFAULT CHARACTER SET utf8 COMMENT 'An instance of a message type (e.g. like a node is an...'; Array ( ) in db_create_table() (line 2753 of /var/www/html/recruiter7110/includes/database/database.inc).

Finally found a solution.I was using Mysql 5.7 on ubuntu 16.04 .AFter downgrading to mysql 5.6 it worked.