superbuild error

I am getting an install error when building v5.6.0 with superbuild (see below) as if there is a prefix missing in front of ‘/lib/python2.7’

my command is:

cmake -DCMAKE_INSTALL_PREFIX=/scratch/leone/jfavre/ParaView/5.6 -DPARAVIEW_CATALYST_PYTHON:BOOL=OFF -DENABLE_mpi:BOOL=ON -DBUILD_TESTING:BOOL=OFF -DENABLE_catalyst:BOOL=OFF -DENABLE_hdf5:BOOL=ON -DENABLE_numpy:BOOL=ON -DENABLE_png:BOOL=ON -DENABLE_python:BOOL=ON -DENABLE_qt5:BOOL=ON ../paraview-superbuild

Error is:

running install_egg_info
Removing /apps/leone/UES/ParaView/src/paraview-superbuildBuild/install/lib/python2.7/lib-dynload/Python-2.7.15-py2.7.egg-info
Writing /apps/leone/UES/ParaView/src/paraview-superbuildBuild/install/lib/python2.7/lib-dynload/Python-2.7.15-py2.7.egg-info
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Exception:
Traceback (most recent call last):
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/commands/install.py", line 342, in run
    prefix=options.prefix_path,
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/req/req_set.py", line 784, in install
    **kwargs
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/req/req_install.py", line 851, in install
    self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/req/req_install.py", line 1064, in move_wheel_files
    isolated=self.isolated,
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/wheel.py", line 345, in move_wheel_files
    clobber(source, lib_dir, True)
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/wheel.py", line 287, in clobber
    ensure_dir(dest)  # common for the 'include' path
  File "/tmp/tmpkQyWTn/pip-9.0.3-py2.py3-none-any.whl/pip/utils/__init__.py", line 83, in ensure_dir
    os.makedirs(path)
  File "/apps/leone/UES/ParaView/src/paraview-superbuildBuild/superbuild/python/src/Lib/os.py", line 150, in makedirs
    makedirs(head, mode)
  File "/apps/leone/UES/ParaView/src/paraview-superbuildBuild/superbuild/python/src/Lib/os.py", line 157, in makedirs
    mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/lib/python2.7'

What package is failing to build?