shared library - Install unetbootin on Ubuntu 12.04

I'm trying to install UNetbootin on Ubuntu 12.04 LTS. I downloaded the executable file from this link and followed the instructions below:

If using Linux, make the file executable (using either the command
chmod +x ./unetbootin-linux, or going to Properties->Permissions and

checking "Execute"), then start the application, you will be prompted
for your password to grant the application administrative rights, then
the main dialog will appear, where you select a distribution and
install target (USB Drive or Hard Disk), then reboot when prompted.\

So I typed on my terminal sudo chmod +x unetbootin-linux-584 and tried to execute the binary file with ./unetbootin-linux-584 but got this output:

./unetbootin-linux-584: error while loading shared libraries:

libXrandr.so.2: cannot open shared object file: No such file or
directory

However when I checked for libraries libXrandr on my system I actually found them

$> locate libXrandr
/usr/lib/x86_64-linux-gnu/libXrandr.so.2
/usr/lib/x86_64-linux-gnu/libXrandr.so.2.2.0
/usr/lib/x86_64-linux-gnu/libXrandr_ltsq.so.2

/usr/lib/x86_64-linux-gnu/libXrandr_ltsq.so.2.2.0

so I really don't have a clue of what's the problem and how can I fix it, any ideas?

My guess is you are trying to run a 32 bit application on a 64 bit host.

unetbootin is in the repos

http://packages.ubuntu.com/search?keywords=unetbootin

sudo apt-get update && sudo apt-get install unetbootin

See also https://help.ubuntu.com/community/InstallingSoftware