The developer of the RAMBo controller used by the TAZ has made available a “signed” version of the driver. This will allow it to be installed on Windows Vista and above without triggering any security warnings due to an un-signed driver. It’s my understanding that Windows 8 will not allow a user to install an un-signed driver, which would preclude them from using the TAZ (or any other RAMBo equipped printer!).
The signed driver archive can be found here: http://www.reprap.org/wiki/File:RAMBo_USBdriver.zip