--- apachesolr.module	2009-10-14 15:08:20.000000000 -0500
+++ apachesolr.module	2009-12-04 16:50:50.448114200 -0600
@@ -276,7 +276,7 @@ function apachesolr_rebuild_index_table(
   db_query("DELETE FROM {apachesolr_search_node}");
   // Populate table
   db_query("INSERT INTO {apachesolr_search_node} (nid, status, changed)
-            SELECT n.nid, n.status, GREATEST(n.created, n.changed, c.last_comment_timestamp) AS changed
+            SELECT n.nid, n.status, GREATEST(n.created, n.changed, IFNULL(c.last_comment_timestamp,0)) AS changed
             FROM {node} n
             LEFT JOIN {node_comment_statistics} c ON n.nid = c.nid");
    // Make sure no nodes end up with a timestamp that's in the future.