I’m reposting Mike Whitby’s post:
On occasion you may have a module which requires both EAV and flat resource setup classes, in this situation you can instantiate a setup class as this note shows.
$installer = Mage::getModel('eav/entity_setup','eav_setup');
$installer = Mage::getResourceModel('core/setup','core_setup');
You can then continue with the setup script as you normally would.
Thank You Mike!