diff --git a/openerp/addons/base/ir/ir_model.py b/openerp/addons/base/ir/ir_model.py
index 76166ee92e0..aca8ac466c8 100644
--- a/openerp/addons/base/ir/ir_model.py
+++ b/openerp/addons/base/ir/ir_model.py
@@ -384,7 +384,7 @@ class ir_model_fields(osv.osv):
 
         # static table of properties
         model_props = [ # (our-name, fields.prop, set_fn)
-            ('field_description', 'string', str),
+            ('field_description', 'string', tools.ustr),
             ('required', 'required', bool),
             ('readonly', 'readonly', bool),
             ('domain', '_domain', eval),
diff --git a/openerp/addons/base/res/res_users.py b/openerp/addons/base/res/res_users.py
index 091273561d9..3b9f84aeb28 100644
--- a/openerp/addons/base/res/res_users.py
+++ b/openerp/addons/base/res/res_users.py
@@ -99,7 +99,7 @@ class res_groups(osv.osv):
     }
 
     _sql_constraints = [
-        ('name_uniq', 'unique (category_id, name)', 'The name of the group must be unique !')
+        ('name_uniq', 'unique (category_id, name)', 'The name of the group must be unique within an application!')
     ]
 
     def search(self, cr, uid, args, offset=0, limit=None, order=None, context=None, count=False):
diff --git a/openerp/tools/convert.py b/openerp/tools/convert.py
index 2f2dcb4a105..79a7f307072 100644
--- a/openerp/tools/convert.py
+++ b/openerp/tools/convert.py
@@ -305,12 +305,17 @@ form: module.record_id""" % (xml_id,)
 
         if d_search:
             idref = _get_idref(self, cr, self.uid, d_model, context={}, idref={})
-            ids = self.pool[d_model].search(cr, self.uid, unsafe_eval(d_search, idref))
+            try:
+                ids = self.pool[d_model].search(cr, self.uid, unsafe_eval(d_search, idref))
+            except ValueError:
+                _logger.warning('Skipping deletion for failed search `%r`', d_search, exc_info=True)
+                pass
         if d_id:
             try:
                 ids.append(self.id_get(cr, d_id))
-            except:
+            except ValueError:
                 # d_id cannot be found. doesn't matter in this case
+                _logger.warning('Skipping deletion for missing XML ID `%r`', d_id, exc_info=True)
                 pass
         if ids:
             self.pool[d_model].unlink(cr, self.uid, ids)
diff --git a/openerp/tools/safe_eval.py b/openerp/tools/safe_eval.py
index 2f280685350..471827b098b 100644
--- a/openerp/tools/safe_eval.py
+++ b/openerp/tools/safe_eval.py
@@ -71,7 +71,8 @@ _SAFE_OPCODES = _EXPR_OPCODES.union(set(opmap[x] for x in [
     'CONTINUE_LOOP', 'RAISE_VARARGS',
     # New in Python 2.7 - http://bugs.python.org/issue4715 :
     'JUMP_IF_FALSE_OR_POP', 'JUMP_IF_TRUE_OR_POP', 'POP_JUMP_IF_FALSE',
-    'POP_JUMP_IF_TRUE', 'SETUP_EXCEPT', 'END_FINALLY', 'LOAD_FAST',
+    'POP_JUMP_IF_TRUE', 'SETUP_EXCEPT', 'END_FINALLY',
+    'LOAD_FAST', 'STORE_FAST', 'DELETE_FAST',
     'LOAD_GLOBAL', # Only allows access to restricted globals
     ] if x in opmap))