diff --git a/addons/document/content_index.py b/addons/document/content_index.py
index 399541e1f59..cde05987f25 100644
--- a/addons/document/content_index.py
+++ b/addons/document/content_index.py
@@ -181,11 +181,11 @@ class contentIndex(object):
                 res = (mime, fobj.indexContent(content,filename,fname or realfname) )
             else:
                 _logger.debug("Have no object, return (%s, None).", mime)
-                res = (mime, None )
+                res = (mime, '')
         except Exception:
             _logger.exception("Cannot index file %s (%s).",
                                     filename, fname or realfname)
-            res = None
+            res = (mime, '')
 
         # If we created a tmp file, unlink it now
         if not realfname and fname:
diff --git a/addons/document/std_index.py b/addons/document/std_index.py
index b20874e72f8..dda776b1ec3 100644
--- a/addons/document/std_index.py
+++ b/addons/document/std_index.py
@@ -105,7 +105,7 @@ class DocIndex(indexer):
             
             _logger.warning("Failed attempt to execute antiword (MS Word reader). Antiword is necessary to index the file %s of MIME type %s. Detailed error available at DEBUG level.", fname, self._getMimeTypes()[0])
             _logger.debug("Trace of the failed file indexing attempt.", exc_info=True)
-            return False
+            return u''
     
 cntIndex.register(DocIndex())
 
@@ -166,9 +166,14 @@ class PdfIndex(indexer):
         return ['.pdf']
 
     def _doIndexFile(self, fname):
-        pop = Popen(['pdftotext', '-enc', 'UTF-8', '-nopgbrk', fname, '-'], shell=False, stdout=PIPE)
-        (data, _) = pop.communicate()
-        return _to_unicode(data)
+        try:
+            pop = Popen(['pdftotext', '-enc', 'UTF-8', '-nopgbrk', fname, '-'], shell=False, stdout=PIPE)
+            (data, _) = pop.communicate()
+            return _to_unicode(data)
+        except OSError:
+            _logger.warning("Failed attempt to execute pdftotext. This program is necessary to index the file %s of MIME type %s. Detailed error available at DEBUG level.", fname, self._getMimeTypes()[0])
+            _logger.debug("Trace of the failed file indexing attempt.", exc_info=True)
+            return u''
 
 cntIndex.register(PdfIndex())