Can't retrieve loader path

[amenk]

git clone git://github.com/fsquillace/junest ~/.local/share/junest
export PATH=~/.local/share/junest/bin:$PATH
junest -f

I am getting

Installing JuNest...
The default mirror URL is https://mirrors.kernel.org/archlinux/$repo/os/$arch.
Remember to refresh the package databases from the server:
    pacman -Syy
JuNest installed successfully
proot error: can't retrieve loader path (/proc/self/fd/)
proot error: execve("/usr/bin/sh"): No such file or directory
proot info: possible causes:
  * the program is a script but its interpreter (eg. /bin/sh) was not found;
  * the program is an ELF but its interpreter (eg. ld-linux.so) was not found;
  * the program is a foreign binary but qemu was not specified;
  * qemu does not work correctly (if specified);
  * the loader was not found or doesn't work.
fatal error: see `proot-x86_64 --help`.
proot warning: can't readlink '/proc/self/cwd': No such file or directory
proot error: can't chmod '/tmp/proot-32515-4Nwwnz': No such file or directory
proot error: can't retrieve loader path (/proc/self/fd/)
proot error: execve("/usr/bin/sh"): No such file or directory
proot info: possible causes:
  * the program is a script but its interpreter (eg. /bin/sh) was not found;
  * the program is an ELF but its interpreter (eg. ld-linux.so) was not found;
  * the program is a foreign binary but qemu was not specified;
  * qemu does not work correctly (if specified);
  * the loader was not found or doesn't work.
fatal error: see `proot-x86_64 --help`.
proot warning: can't readlink '/proc/self/cwd': No such file or directory
proot error: can't chmod '/tmp/proot-32517-srmF4z': No such file or directory

What does that mean? How can I fix it?

It's a HostEurope Managed Server on Debian 8