Error updating 2.16.1 to 3.0.0

We are using Piwik 2.16.1 on Windows Server 2012 R2 and are looking to update to version 3.0.0. I logged in as an administrator to the Piwik web console, and tried to run the automatic update, but received an error about writing to some directories. Unfortunately, the error message has some formatting errors making it difficult to read the suggested actions (see attached)

I tried following the manual update procedure (from this page but I am unable to copy/backup the config.ini.php file to another directory, even as a domain admin with full privileges to the server.

Can anyone offer any advice on upgrading to 3.0.0?

Fixed - had to allow localhost\IIS_IUSR account full permissions to the C:\inetpub\wwwroot\piwik\tmp directory