If you use qtranslate or qtranslate-x to translate your webiste, and, you also use acf (advanced custom fields), it is probably that you installed the acf-qtranslate plugin because it adds extra field types that are more appropriate for multi language sites due to an easier display (i.e: a textarea that has N tabs and each tab is a language).
When you perform an analysis using tools such as firebug, you can notice an error like the following:
TypeError: acf.o is null
In this case the only solution is to update the plugin because this issue is fixed since the 4.4.1 version.
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