i think i found the problem...i took out a tree i made and it rendered. the tree is made from nurbs....i think my comp for some annoying reason couldnt take it. its the only thing i can think of. i shall render the tree separatly and hope it will do so i can composite it.

if it still doent render....i shall convert to polys..do you think this is in with a chance of working? i hope so.

i have attached the file for anyone who may want to have a go and see if it is my comp.
any ideas welcome

thanks