I have tried and the demo worked very well. I went to look at the log report in drupal, here are the error messages, can anybody help me figure out what's wrong? In case you need to know, my drupal database tables have prefix (cmdr7), and drupal db and civicrm db are separate, and the databases are named like this: sitename_drupal, sitename_civicrm. Thank you!
log 1:
Location http://host/sitename/index.php?q=civicrm/ajax/jqCounty&_id=address_1_state_province_id&_name=address%5B1%5D%5Bstate_province_id%5D&_value=null
Referrer http://host/sitename/index.php?q=civicrm/contact/add&reset=1&action=update&cid=102
Message $Fatal Error Details = Array ( [message] => One of parameters (value: null) is not of the type Integer [code] => )
log 2:
Location http://host/sitename/index.php?q=civicrm/ajax/jqCounty&_id=address_1_state_province_id&_name=address%5B1%5D%5Bstate_province_id%5D&_value=null
Referrer http://host/sitename/?q=admin%2Freports%2Fevent%2F19609&render=overlay
Message $backTrace = /usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Core/Error.php, backtrace, 303
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Utils/Type.php, fatal, 282
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Core/DAO.php, validate, 933
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Core/DAO.php, composeQuery, 870
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Core/PseudoConstant.php, executeQuery, 1545
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Core/Page/AJAX/Location.php, countyForState, 242 , jqCounty,
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/CRM/Core/Invoke.php, call_user_func, 191
/usr/local/apache2/htdocs/sitename/sites/all/modules/civicrm/drupal/civicrm.module, invoke, 447 , civicrm_invoke,
/usr/local/apache2/htdocs/sitename/includes/menu.inc, call_user_func_array, 503
/usr/local/apache2/htdocs/sitename/index.php, menu_execute_active_handler, 21