[IMP] base: error message understandable by humans

closes odoo/odoo#56139

Signed-off-by: Richard Mathot (rim) <rim@openerp.com>

odoo/addons/base/models/ir_module.py

@@ -580,8 +580,9 @@ class Module(models.Model):
             # during execution, the lock won't be released until timeout.
             self._cr.execute("SELECT * FROM ir_cron FOR UPDATE NOWAIT")
         except psycopg2.OperationalError:
-            raise UserError(_("The server is busy right now, module operations are not possible at"
-                              " this time, please try again later."))
+            raise UserError(_("Odoo is currently processing a scheduled action.\n"
+                              "Module operations are not possible at this time, "
+                              "please try again later or contact your system administrator."))
         function(self)
 
         self._cr.commit()