You are missing the following 32bit libraries, and Steam may not run:
libXrandr.so.2
libpangoft21.0.so.0
libpango1.0.so.0
libfreetype.so.6
libfontconfig.so.1
libgobject2.0.so.0
libglib2.0.so.0
libgtkx112.0.so.0
libgtkx112.0.so.0
libgdkx112.0.so.0
libpangocairo1.0.so.0
libgdk_pixbuf2.0.so.0
libcairo.so.2
libpango1.0.so.0
libfreetype.so.6
libfontconfig.so.1
libgobject2.0.so.0
libglib2.0.so.0
libXi.so.6
libasound.so.2
libXrender.so.1
libnss3.so
libnssutil3.so
libsmime3.so
libplc4.so
libnspr4.so
libdbus1.so.3
libpng12.so.0
libcups.so.2
libgcrypt.so.11



You need to add the foreign arch i386 to make i386 packages available.



I think you have 64bit Ubuntu, if so, try this: Open up a terminal (Ctrl + Alt + F1).
A reboot may be required 


I have same problem and I have 64bit Ubuntu 13.10. So I installed Ubuntu 14.04, the same problem occurs.
Now launching Steam there is this warning:
These libraries are not available, but Steam runs fine on 14.04 for me even with this warning. 

