Index: openacs-4/packages/forums/lib/message/thread-chunk.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/forums/lib/message/thread-chunk.tcl,v
diff -u -N -r1.5.6.2 -r1.5.6.3
--- openacs-4/packages/forums/lib/message/thread-chunk.tcl	22 Jun 2007 15:50:44 -0000	1.5.6.2
+++ openacs-4/packages/forums/lib/message/thread-chunk.tcl	27 Jun 2007 13:23:31 -0000	1.5.6.3
@@ -78,7 +78,11 @@
 
 # More Tcl vars (we might as well use them - Ben)
 if { [string equal $forum(presentation_type) flat] } {
-    set order_by "t.posting_date, tree_sortkey"
+        if { [db_type] == "postgresql" } {
+                set order_by "t.posting_date, tree_sortkey"
+        } else {
+                set order_by "posting_date, tree_sortkey"
+        }
 } else {
     set order_by "tree_sortkey"
 }