Index: openacs-4/packages/tsearch2-driver/tcl/tsearch2-driver-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/tsearch2-driver/tcl/tsearch2-driver-procs.tcl,v
diff -u -N -r1.29 -r1.29.2.1
--- openacs-4/packages/tsearch2-driver/tcl/tsearch2-driver-procs.tcl	30 Mar 2013 18:19:48 -0000	1.29
+++ openacs-4/packages/tsearch2-driver/tcl/tsearch2-driver-procs.tcl	28 Aug 2013 23:08:36 -0000	1.29.2.1
@@ -265,6 +265,9 @@
         regsub -all {\(|\)} $query {} query
     }
 
+    # remove empty ()
+    regsub -all {\(\s*\)} $query {} query
+
     # remove or at beginning of query 
     regsub -nocase "^or " $query {} query
     # replace boolean words with boolean operators