I downloaded & ran the sample installer.
It gave me no indication whatsoever of where it would install, and no chance to change it!
First a question: Where did it go??
But please fix this so that, at the *very* least, it says where it will install and, vastly preferable, it allows the user to choose the location.
Why does it have to be an installer at all? Can't it just be supplies as a ZIP or whatever - as is usual for source code?
The Datasource uses an installer because the files must go to specific locations so the DSM can find them.
The 32 bit source goes into the %windir%\twain_32\sub folder
The 64 bit source goes into the %windir%\twain_64\sub folder
Adding this information on the installer would be useful to the user.
The source code is a separate file. And it is a zip.
Maybe think about using nullsoft? Easier to customize, and shows where everything was put.