Magento Installation – Install Magento Without Sample Data

Your magento does not install properly.

May be one or more tables has been missing from your database.

You need to reinstall your magento system properly.

May be execution time was exceed during the installation process. For this case you increase max execution time in php.

If you are trying to create an EAV entity, you need a record for that entity in the eav_entity_type table.
This needs to be inserted when the module is installed.
For this you need to make your install-0.1.0.php look like this:

<?php 
//you might want to create tables here also
$this->installEntities();

your config.xml should contain this under the global tag

    <resources>
        <complex_setup>
            <setup>
                <module>Eav_Complex</module>
                <class>Eav_Complex_Model_Resource_Setup</class>
            </setup>
        </complex_setup>
    </resources>

and your class Eav_Complex_Model_Resource_Setup should contain this method:

public function getDefaultEntities(){
    $entities = array();
    $entities['complex_complexpost'] = array(
            'entity_model'                  => 'complex/complexpost',
            'attribute_model'               => 'complex/resource_eav_attribute', //this might not be needed
            'table'                         => 'complex/complexpost', //might not be needed
            'additional_attribute_table'    => 'complex/eav_attribute', //might not be needed
            'entity_attribute_collection'   => 'complex/complex_attribute_collection',
            'attributes'        => array( //list here all your entity attributes
                    'title' => array(
                        'group'          => 'General',
                        'type'           => 'varchar',
                        'backend'        => '',
                        'frontend'       => '',
                        'label'          => 'Title',
                        'input'          => 'text',
                        'source'         => '',
                        'global'         => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE,
                        'required'       => '1',
                        'user_defined'   => false,
                        'default'        => '',
                        'unique'         => false,
                        'position'       => '10',
                        'note'           => '',
                        'visible'        => '1',
                        'wysiwyg_enabled'=> '0',
                    ),
             ),
         );
     return $entities;
}

I hope I've closed all the brackets and parentheses.
You will end up with a bunch of new errors after this because you have a log of files still missing, but it should solve your entity type problem.
For a full description on how to create an eav entity, check this question: How to create an EAV entity?