Dear RichP714,
Please open "CuteSoft_Client\CuteEditor\Dialogs\Tag\tag_a.ascx", search the following line:
<input type="checkbox" name="Nofollow" id="Nofollow" value="Nofollow" />
change it to:
<input type="checkbox" checked = "checked" name="Nofollow" id="Nofollow" value="Nofollow" />
Thanks for asking