Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 11765)
+++ wp-includes/wp-db.php	(working copy)
@@ -695,7 +695,7 @@
 			}
 			// Return number of rows affected
 			$return_val = $this->rows_affected;
-		} else {
+		} else if(!is_bool($this->result)) {
 			$i = 0;
 			while ($i < @mysql_num_fields($this->result)) {
 				$this->col_info[$i] = @mysql_fetch_field($this->result);