Word 2010 - Adding form field to table

I have a table开发者_开发技巧 within word which is protected, but I want to add a user text form field into the table:

For some reason when trying to do it I get: 'You cannot paste form fields into, comments, headers, footer, footnotes, endnotes, or text boxes'

It's ok sussed it out, the table was actually embedded within a text box and wasn't allowing the control to be added.