This error indicates Zwift is having difficulty accessing the Documents folder for the user account. There are a few reasons this may happen. They include:
- You are not an Admin on this machine
- The Documents folder is locked
- The Documents folder does not exist
Try right-clicking on the ZwiftInstaller file and then choosing 'Run as Admin...' even if you already have admin access. Additionally make sure your 'Documents' actually exists. In some instances, especially for Enterprise machines, the 'Documents' folder can be remote and not exist unless the computer is connected to a VPN.
In any case, if a company machine, we recommend contacting your I.T. department for further assistance.