I was installing the apiconnect developer toolkit last night to run through a couple of labs on behalf of a customer.
Usually that just requires running 'npm install -g apiconnect' and the job is done.
The laptop installation failed unexpectedly and so I started to troubleshoot by looking through the installation log file. After far too long I though it could be the version of Node/npm as this is on a new laptop.
The npm version was 6.7.0. Node was 11.4.0
I uninstalled node and installed version 10.15.1 of node instead which adds npm 6.4.1.
Running npm install -g apiconnect' then worked properly and I could get on with the lab.
The node.js / npm version were probably too new and the install script had not been able to complete. The older versions worked well.
In retrospect - I downgraded Node.js to the LTS version.