If you are not doing so, try to start the program from the terminal. If there is a missing library, it will output an error message. Like this game:
Code:
dmn@Sydney:~/games/thomasLinuxStandalone$ ./thomasWasAlone
./thomasWasAlone: error while loading shared libraries: libGLU.so.1: cannot open shared object file: No such file or directory
Then you have to find the package that supplies the needed library using Ubuntu Package Search:
http://packages.ubuntu.com/
and install it.
Then repeat.
By the way, the "add-architecture" is no longer necessary (in olden times, it used to be). You were correct that 32-bit support is already there. To verify:
From my U 23.10:
Code:
dmn@Kayleigh:~$ dpkg --print-foreign-architectures
i386