Index: includes/database/database.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/database/database.inc,v
retrieving revision 1.88
diff -u -r1.88 database.inc
--- includes/database/database.inc	3 Jan 2010 06:50:07 -0000	1.88
+++ includes/database/database.inc	5 Jan 2010 03:22:09 -0000
@@ -1445,6 +1445,10 @@
 
     _db_check_install_needed();
 
+    // if we are installing, we may not have a database configured yet
+    if (!is_array($databases))
+      return;
+
     $databaseInfo = $databases;
     foreach ($databaseInfo as $index => $info) {
       foreach ($databaseInfo[$index] as $target => $value) {