Just FYI, this just means you don't have the Virtualmin Apache packages installed (which are installed when using the install.sh script).
The Virtualmin Apache packages are near-identical to the distro-specific ones, except that suexec is compiled to work on /home.
So, you can definitely solve it by recompiling, but another method is just to grab the Virtualmin files --
http://software.virtualmin.com if you have the Pro version, and
http://software.virtualmin.com/gpl/ if you have Virtualmin GPL.
-Eric