Si no me equivoco puede correr en Windows también, en el FAQ de la web oficial de Webmin dice esto:
# Is there a version of Webmin for Windows?
As of Webmin version 1.310, it is possible to install on Windows using the included setup.pl script. However, this is extremely alpha-level code, and only a few of the Webmin modules work due to packages like Squid, Sendmail and so on not existing under Windows. In addition, the Windows security and permissions systems are quite different from Unix, so anything that deals with file ownership and modes may not work.
Saludos.