At http://wpkg.org/Tuxpaint there are command lines listed for a silent install. I used this with a scripted installation tool to attempt a silent install of TuxPaint 0.9.21.
Tux Paint installed correctly using the command line "tuxpaint-0.9.21-win32-installer.exe SP- /silent /norestart /nocancel"
Tux Paint Stamps failed to install using the command line "tuxpaint-stamps-2008.03.01-win32-installer.exe SP- /silent /norestart /nocancel" (changed to the name of the version I have which is 2009 something)
The message returned by the scripting system is "Returned an unexpected return code: 2"
And I verified that the stamps have not been installed.