To run 32 bit apps on 64 bit Debian / Ubuntu based Systems, you need to have installed ia32-libs.
To check if you have ia32-libs installed on your system, use this command:
$ dpkg -l ia32-libs
If you get an output like this: ii ia32-libs, you have ia32-libs installed.
Else, you have to install it by hand, with apt-get install:
$ sudo apt-get install ia32-libs