This error is coming from your operating system (not Vectorworks itself) and normally indicates that the you don't have read/write access to your Vectorworks folder.
Please follow the steps below:
- Quit Vectorworks.
- In your Application folder, right click on the Vectorworks 2017 folder and choose "Get Info"
- Set the permissions so that each listed user (System, YourUsername, etc) is allowed to Read and Write.
- Then, click the lock at the bottom right, unlock it with your admin password if prompted
- Click the gear and choose "Apply to enclosed items" like so, it may take a few moments to finish:
6. Reboot your machine, then restart Vectorworks and try installing the libraries,
This permission adjustment normally fixes this error, errors within the Package Manager, and/or failure to download the updates to the packages when the application first launches.