Not able to create a new site

I am not able to install erpnext into my new production server:
I am getting the folowing error when i execute

bench new-site amc.erpnext
.

INFO:bench.utils:creating new site amc.erpnext
frappe app is not installed. Run the following command to install frappe
bench get-app https://github.com/frappe/frappe.git
/bin/sh: 1: /home/erpnext/frappe-bench/env/bin/frappe: not found
Traceback (most recent call last):
  File "/usr/local/bin/bench", line 9, in <module>
    load_entry_point('bench', 'console_scripts', 'bench')()
  File "/home/erpnext/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/erpnext/bench-repo/bench/commands/make.py", line 56, in new_site
    new_site(site, mariadb_root_password=mariadb_root_password, admin_password=admin_password)
  File "/home/erpnext/bench-repo/bench/utils.py", line 150, in new_site
    ), cwd=os.path.join(bench_path, 'sites'))
  File "/home/erpnext/bench-repo/bench/utils.py", line 127, in exec_cmd
    raise CommandFailedError(cmd)
bench.utils.CommandFailedError: /home/erpnext/frappe-bench/env/bin/frappe amc.erpnext --install 56458b1779 

what could be the error. pls help me out

regards,

Error itself telling that frappe-app is not installed properly.

@ninjas Install the frappe app

bench get-app https://github.com/frappe/frappe.git

execute the above command from your frappe-bench folder