Msistuff.exe and Setup.exe are two important binaries are needed to create MSI bootstraper. Unfortunately you need to download the whole Windows SDK to access these binaries.
Fortunately there are pre-built msistuff.exe and setup.exe binaries available from WIX examples page:
http://sourceforge.net/tracker/?group_id=105970&atid=654188
Download the Bootstraper example from this page.
