Many thanks for your comments, it seems that I'm not alone with my problems.
I get an error message with all Firefly renders within a few minutes telling me that there isn't enough memory (I have 2GIG - how much does it want?) so my recent reders have been with the P4 which isn't bad but limits you to renders of 4000 X 4000 which is smaller than I would normally use.
I too would render outside of Poser if it were an option but I don't like Bryce and Vue 5 inf can't render the Poser hair properly.
Thanks again for your feedback.
Tony