Thanks cuavas, appreciate the reply.
I've done as suggested and its just not working for me, I've even gone the route of ignoring the signature as well.
Later on tonight when I have time I will do another full clean install and try once more, if it still doesn't work I'll just give up compiling until it gets fixed eventually... (as a year or so ago I had a similar problem that I couldn't fix for a few months until it got sorted on its own).
Thanks again.
Mordor