We had the very same problem here, answer we got from edge cam was that our post is not "adaptive". But for a small $2000 fee they would convert it to an adaptive post for us... We use the SECO Carboloy thread milling wizard. If you have more than one hole to thread mill, simply use a drill cycle to get your positional locations, edit the G81 line, and use the Carboloy program in incremental as a sub program to machine the threads. If you only have one thread, the Carboloy program will work..It is a free download, simply visit there website and go from there.
Hope this helps.