loadJSArray returns "Not a Function" Error

We are trying to pass data to a tree using the loadJSArray function but are getting an error that the function does not exist.

Script file…/ext/dhtmlxtree_json.js has been included in the project, but it still cannot find the function.

loadJSArray defined on line 64 of dhtmlxtree_json.js, please reffer to
    support@dhtmlx.com )