Hello, the link is http://zoiper.com/downloads/zoiper220-linux.tar.gz
A 64 bit ubuntu can run a 32 bit application, you just need to install the crossplatform support libraries.
Note that Zoiper Classic requires Alsa to run, it might not be installed by default on your Ubuntu.
Please open a terminal, use cd to navigate to the folder where the zoiper executable resides and run
ldd zoiper | grep -i not
The output of the command will help you determine if there are some missing libraries.