Please update your WPML plugin to the latest version 4.6.6, and add-ons to benefit from the latest bug fixes and improvements. This may not necessarily resolve your problem, however, in order to troubleshoot the issue best, we need to work on the latest code available. Make sure also to update your WordPress.
You can check the latest released versions under "My Account -> Downloads" on this site. Instructions to update can be found here: http://wpml.org/faq/install-wpml/
Please remember to back up your database first before you proceed. You can use a plugin for this if you like (example: http://wordpress.org/plugins/duplicator/)