nvm: /usr/bin/env: node: No such file or directory

I’m trying to install Node.js on my Netgear ReadyNAS (Architecture = ARM v71) using this method

cd /home/admin
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.1/install.sh | bash
source .bashrc
nvm install 6.9.1

But I got an error after the last command

/usr/bin/env: node: No such file or directory

See complete result

admin@ReadyNAS:~$ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.1/install.sh | bash
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  7766  100  7766    0     0  22631      0 --:--:-- --:--:-- --:--:-- 22707
=> Downloading nvm from git to '/home/admin/.nvm'
=> Cloning into '/home/admin/.nvm'...
remote: Counting objects: 6025, done.
remote: Compressing objects: 100% (13/13), done.
remote: Total 6025 (delta 5), reused 0 (delta 0), pack-reused 6012
Receiving objects: 100% (6025/6025), 1.71 MiB | 805.00 KiB/s, done.
Resolving deltas: 100% (3751/3751), done.
Checking connectivity... done.
* (detached from v0.31.1)
  master

=> Appending source string to /home/admin/.bashrc
=> Close and reopen your terminal to start using nvm
admin@ReadyNAS:~$ source .bashrc
admin@ReadyNAS:~$ nvm install 6.9.1
Downloading https://nodejs.org/dist/v6.9.1/node-v6.9.1-linux-armv7l.tar.xz...
######################################################################## 100.0%
/usr/bin/env: node: No such file or directory
nvm is not compatible with the npm config "prefix" option: currently set to ""
Run `nvm use --delete-prefix v6.9.1` to unset it.

What am I doing wrong ? (I already used this method on a x86 64 bit Ubuntu machine and on a Mac Mini … and it works fine)