Since in Ubuntu 13.10 64bits there is no more the "ia32libs" you need to follow the next steps:
There are 2 options to run Machinarium on Ubuntu 13.10 64bits.
Deb Package
If we have the .deb package (and yes! it is a 32bit package).
You must to install it with Ubuntu Software Center (not using dpkg -i), so simply double click the file.
To remove the game
sudo dpkg -r machinarium
TAR.GZ version
If you have the tar.gz version.
You need to install all those libraries.
sudo apt-get install libgtk2.0-0:i386 libnss3:i386 libcurl3-gnutls:i386 libidn11:i386 libpango1.0-0:i386 libpangox-1.0-0:i386 libpangoxft-1.0-0:i386 librtmp0:i386 libxft2:i386
Run it on STEAM
In both cases if you want to run it with STEAM as a NO Steam game, you must to install also this last library.
sudo apt-get install libxtst6:i386
The original link here:
http://askubuntu.com/questions/356605/ubuntu-13-10-64-bit-machinarium-error-while-loading-shared-libraries-libgtk-x1/399355#399355