I've been having similar problems for several versions. It always does a rollback after the progress bar gets to the end, and then says it failed to install.
I finally found a way around the problem. I used Universal Extractor to uncompress the MSI using the first option given (Admin).
http://legroom.net/software/uniextract
Afterward I simply copied the directory /Calibre/ into my Program Files directory and ran calibre.exe. Works like a charm.