When you install SharePoint Beta 2 to go with your PowerPivot for SharePoint CTP3 install, some will install SharePoint on a set of servers (or VMs) that do not have internet connectivity.
The first step to installing SharePoint Beta 2 is to run the SharePoint Prerequisite Installer. If you are in a lab environment that does not have internet connectivity, this step will fail because it is trying to download the required files.
Within the installer dialog, it will provide you a link to the installation log. Search for “download” within the file and you can then identify the component and URL it was trying to download from. Copy the URL to a box that has internet connectivity to download that file, place it in a location your lab machine can get access to, run the component, and then you can then proceed with the next step of your installation.
The operational issue here is that there are potentially seven different components that you need to download so going through the step of downloading, running the Prerequisite Installer, running into an error, identifying the component and URL, downloading it, running the component, continuing… is a tad daunting. To help things out, below are the links to the files required for the SharePoint Prerequisite Installer for Windows Server 2008 (they are slightly different for Windows Server 2008 R2 – mainly the first step).