problem running demo of Flow past a dolphin using CBC.PDESys

I want to solve system of pde using fenics.
My problem is like flow past a dolfin demo(CBC.PDESys,Specifying large systems of PDEs with ease)
while i am running the demo program Flow past a dolphin i am getting following errors like,

TypeError: unsupported operand type(s) for +: 'Form' and 'Inner'
palraj@palraj-Inspiron-1545:~/Desktop/rough$ python cbcdolfin.py
Creating new work vector for up
Adding PDESubSystem: NavierStokes
Adding ['linear_solver']['up'] = lu to pdesubsystem up
Adding ['iteration_type'] = Picard to pdesubsystem up
Traceback (most recent call last):
  File "cbcdolfin.py", line 39, in <module>
    NStokes.pdesubsystems['up'] = NavierStokes(vars(NStokes), ['u', 'p'], bcs=bc,reassemble_lhs=False)
  File "/home/palraj/Desktop/rough/cbc/pdesys/PDESubSystems.py", line 331, in __init__
    self.define()
  File "/home/palraj/Desktop/rough/cbc/pdesys/PDESubSystems.py", line 337, in define
    self.get_form(form_args)
  File "/home/palraj/Desktop/rough/cbc/pdesys/PDESubSystems.py", line 301, in get_form
    F = self.form(**form_args)
  File "cbcdolfin.py", line 36, in form
    inner(p, div(v_u))*dx + inner(div(U), v_p)*dx - \
TypeError: unsupported operand type(s) for +: 'Form' and 'Inner'