When attempting to install T4 22.214.171.124 on Windows 7 I got the following errors:
The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2908.
An error occurred during the installation of assembly 'T4Toolbox,version="126.96.36.199",culture="neutral",publicKeyToken="7E313ACCBCCE84DC",processorArchitecture="x86"'. Please refer to Help and Support for more information.
The installation then rolled back.