Quick Search broken if partial match string is entered

This is a very recent bug (triggered by some change in the past few days)

Type 'ada' into quick search box (nav bar) and hit enter.
Expected behavior: Brings up Find Contacts w/ 'ada' in sort_name field

Current behavior: Fatal error cid (value: ) is not of the type Positive
(URL is http://localhost/dgg/d634/civicrm/contact/view?reset=1&cid= instead of search/basic)

Backtrace:
/Users/dgg/svn/trunk/CRM/Core/Error.php, backtrace, 291
/Users/dgg/svn/trunk/CRM/Utils/Type.php, fatal, 268
/Users/dgg/svn/trunk/CRM/Utils/Request.php, validate, 100
/Users/dgg/svn/trunk/CRM/Contact/Page/View.php, retrieve, 108
/Users/dgg/svn/trunk/CRM/Contact/Page/View/Summary.php, preProcess, 56
/Users/dgg/svn/trunk/CRM/Contact/Page/View/Summary.php, preProcess, 94
/Users/dgg/svn/trunk/CRM/Core/Invoke.php, run, 223
/Users/dgg/svn/trunk/drupal/civicrm.module, invoke, 355
, civicrm_invoke,
/Users/dgg/htdocs/d634/includes/menu.inc, call_user_func_array, 348
/Users/dgg/htdocs/d634/index.php, menu_execute_active_handler, 18