Fresh Installtion of Frappe shows Error

HI everybody,

I am installing ERPNext on Ubuntu 16.04
I gave the command bench init frappe-bench && cd frappe-bench

Then it shows the following error,
Traceback (most recent call last):
File “/usr/local/bin/bench”, line 9, in
load_entry_point(‘bench’, ‘console_scripts’, ‘bench’)()
File “/home/user/ERPNext-Khalifa/bench-repo/bench/cli.py”, line 40, in cli
bench_command()
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 716, in call
return self.main(*args, **kwargs)
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 696, in main
rv = self.invoke(ctx)
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 1060, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 889, in invoke
return ctx.invoke(self.callback, **ctx.params)
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 534, in invoke
return callback(*args, **kwargs)
File “/home/user/ERPNext-Khalifa/bench-repo/bench/commands/make.py”, line 19, in init
verbose=verbose, clone_from=clone_from)
File “/home/user/ERPNext-Khalifa/bench-repo/bench/utils.py”, line 56, in init
get_app(frappe_path, branch=frappe_branch, bench_path=path, build_asset_files=False, verbose=verbose)
File “/home/user/ERPNext-Khalifa/bench-repo/bench/app.py”, line 73, in get_app
install_app(app=app_name, bench_path=bench_path, verbose=verbose)
File “/home/user/ERPNext-Khalifa/bench-repo/bench/app.py”, line 103, in install_app
find_links=find_links))
File “/home/user/ERPNext-Khalifa/bench-repo/bench/utils.py”, line 127, in exec_cmd
raise CommandFailedError(cmd)

Any Idea? I just installed all the prerequisies.
bench.utils.CommandFailedError: frappe-bench/env/bin/pip install -q -e frappe-bench/apps/frappe

Try deleting the frappe-bench folder and try again.