Can you post the install log here please /var/log/nodered-install.log
Copy/paste it if possible, using the </> button.
There may be multiple install logs in there, in which case just the last one.
[Edit] Also what to the commands node -v and npm -v show?
It seems you have been using nvm to manage versions of nodejs. The install script doesn't handle that I don't think.
I believe that if you want to use nvm then you will have to do the node red install manually.
I am not sure what you really mean. I have followed an instruction how to install Node-Red 0.27 (something around that version) and now I have upgraded to that new version. Can you tell me what to do in order to install it properly?
I don't care if I manage versions of nodejs with nvm or something else ....
Which instructions did you follow? If it told you to use nvm then it led you up the garden path.
nvm (Npm Version Manager?) is a tool for managing multiple versions of npm. I don't know how to get rid of it. Perhaps someone else does.