The InsertParagraph() method is introduced with our Q2 2014 release in Service Pack 1. You can update your version of the suite in order to have all introduced features and fixes or replace the method with formatting symbol insertion:
Please note that in the next version of the control we will introduce a change concerning the FormattingSymbolLayoutBox class. For now, the above code breaks the current paragraph, but after the change it will simply insert the paragraph end symbol.
Hope this helps.
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