diff --git a/modules/bibrank/lib/bibrank_citation_searcher.py b/modules/bibrank/lib/bibrank_citation_searcher.py
index 98e08b79b..307b6a55e 100644
--- a/modules/bibrank/lib/bibrank_citation_searcher.py
+++ b/modules/bibrank/lib/bibrank_citation_searcher.py
@@ -1,104 +1,110 @@
 # -*- coding: utf-8 -*-
 ##
 ## $Id$
 ##
 ## This file is part of CDS Invenio.
 ## Copyright (C) 2002, 2003, 2004, 2005, 2006 CERN.
 ##
 ## CDS Invenio is free software; you can redistribute it and/or
 ## modify it under the terms of the GNU General Public License as
 ## published by the Free Software Foundation; either version 2 of the
 ## License, or (at your option) any later version.
 ##
 ## CDS Invenio is distributed in the hope that it will be useful, but
 ## WITHOUT ANY WARRANTY; without even the implied warranty of
 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 ## General Public License for more details.
 ##
 ## You should have received a copy of the GNU General Public License
 ## along with CDS Invenio; if not, write to the Free Software Foundation, Inc.,
 ## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 
 from marshal import loads
 from zlib import decompress
 
-from invenio.dbquery import run_sql
+from invenio.dbquery import run_sql, OperationalError
 
 def init_cited_by_dictionary():
     """return citation list dictionary from rnkCITATIONDATA
     """
     query = "select citation_data from rnkCITATIONDATA"
-    compressed_citation_dic = run_sql(query)
+    try:
+        compressed_citation_dic = run_sql(query)
+    except OperationalError:
+        compressed_citation_dic = []
     citation_dic = None
     if compressed_citation_dic and compressed_citation_dic[0]:
         citation_dic = loads(decompress(compressed_citation_dic[0][0]))
     return citation_dic
 
 def init_reference_list_dictionary():
     """return reference list dictionary from rnkCITATIONDATA
     """
     query = "select citation_data_reversed from rnkCITATIONDATA"
-    compressed_ref_dic = run_sql(query)
+    try:
+        compressed_ref_dic = run_sql(query)
+    except OperationalError:
+        compressed_ref_dic = []
     ref_dic = None
     if compressed_ref_dic and compressed_ref_dic[0]:
         ref_dic = loads(decompress(compressed_ref_dic[0][0]))
     return ref_dic
 
 cache_cited_by_dictionary = init_cited_by_dictionary()
 cache_reference_list_dictionary = init_reference_list_dictionary()
 
 ### INTERFACE
 
 def calculate_cited_by_list(record_id, sort_order="d"):
     """Return a tuple of ([recid,citation_weight],...) for all the
        record in citing RECORD_ID.  The resulting recids is sorted by
        ascending/descending citation weights depending or SORT_ORDER.
     """
     citation_list = []
     result = []
     # determine which record cite RECORD_ID:
     if cache_cited_by_dictionary:
         citation_list = cache_cited_by_dictionary.get(record_id, [])
     # get their weights:
     query = "select relevance_data from rnkMETHODDATA, rnkMETHOD WHERE rnkMETHOD.id=rnkMETHODDATA.id_rnkMETHOD and rnkMETHOD.name='cit'"
     compressed_citation_weight_dic = run_sql(query)
     if compressed_citation_weight_dic and compressed_citation_weight_dic[0]:
         citation_dic = loads(decompress(compressed_citation_weight_dic[0][0]))
         for id in citation_list:
             tmp = [id, citation_dic[id]]
             result.append(tmp)
     # sort them:
     if result:
         if sort_order == "d":
             result.sort(lambda x, y: cmp(y[1], x[1]))
         else:
             result.sort(lambda x, y: cmp(x[1], y[1]))
     return result
 
 def calculate_co_cited_with_list(record_id, sort_order="d"):
     """Return a tuple of ([recid,co-cited weight],...) for records
        that are co-cited with RECORD_ID.  The resulting recids is sorted by
        ascending/descending citation weights depending or SORT_ORDER.
     """
     result = []
     result_intermediate = {}
     citation_list = []
     if cache_cited_by_dictionary:
         citation_list = cache_cited_by_dictionary.get(record_id, [])
     for cit_id in citation_list:
         reference_list = []
         if cache_reference_list_dictionary:
             reference_list = cache_reference_list_dictionary.get(cit_id, [])
         for ref_id in reference_list:
             if not result_intermediate.has_key(ref_id):
                 result_intermediate[ref_id] = 1
             else: result_intermediate[ref_id] += 1
     for key, value in result_intermediate.iteritems():
         if not (key==record_id):
             result.append([key, value])
     if result:
         if sort_order == "d":
             result.sort(lambda x, y: cmp(y[1], x[1]))
         else:
             result.sort(lambda x, y: cmp(x[1], y[1]))
     return result