=== modified file 'bin/addons/base/res/res_lang.py'
--- bin/addons/base/res/res_lang.py	2010-09-02 11:31:42 +0000
+++ bin/addons/base/res/res_lang.py	2011-01-18 12:28:28 +0000
@@ -123,6 +123,10 @@
         lang_grouping, thousands_sep, decimal_point = self._lang_data_get(cr, uid, ids[0], monetary)
 
         formatted = percent % value
+        
+        if not formatted: 
+            return '0'
+
         # floats and decimal ints need special action!
         if percent[-1] in 'eEfFgG':
             seps = 0