adding more info for --passwords

plugins/generic/enumeration.py

@@ -370,6 +370,8 @@ class Enumeration:
         if not kb.data.cachedUsersPasswords:
             errMsg = "unable to retrieve the password "
             errMsg += "hashes for the database users "
+            errMsg += "(most probably due to problems "
+            errMsg += "with backend DBMS user permissions)"
             raise sqlmapNoneDataException, errMsg
 
         message = "do you want to use dictionary attack on retrieved password hashes? [Y/n/q]"