I have found a possible solution for those who can't install the wgt app launcher, due this error:
"An error has occurred while applying security settings. Users is not a valid user or group." This could be a problem with the package or a problem connecting to a domain controller on the network. Check your network connecting and click retry or cancel to end install"
This is a Windows message telling you that the group called “Users” is missing. You can use Basics, which set the security permissions in Windows to allow access for all users.
The most common reason for not having a group called Users is because you are using a non-English language version (as the system can't find the group named "Users"). You will need to create a new group and name it “Users”
1) Right-click on My Computer and select Manage.
2) Open the Local Users and Group tree.
3) Open the Groups folder and search for a profile named Users. If not found, right-click on the Groups folder and select New Group. Type in Users (case sensitive) as the New Group name and select Create.
4) Open the Groups folder and search for a profile named Administrators. If not found, right-click on the Groups folder and select New Group. Type in Administrators (case sensitive) as the New Group name and select Create.
5) Close the Computer Management window, restart the system