addrsrch_fullname needs to default to one of its allowable values

include/load_prefs.php

@@ -261,7 +261,7 @@ $show_html_default =
    getPref($data_dir, $username, 'show_html_default', SMPREF_ON);
 
 $addrsrch_fullname =
-   getPref($data_dir, $username, 'addrsrch_fullname', SMPREF_ON);
+   getPref($data_dir, $username, 'addrsrch_fullname', 'fullname');
 
 $enable_forward_as_attachment =
    getPref($data_dir, $username, 'enable_forward_as_attachment', SMPREF_ON);