Missing /lib/libc.so.6

A quick solution.

Open a terminal (Ctrl+Alt+T) and run the following commands:

For 64-bit Ubuntu:

sudo ln -s /lib64/x86_64-linux-gnu/libc.so.6 /lib64/libc.so.6

For 32-bit Ubuntu:

sudo ln -s /lib/i386-linux-gnu/libc.so.6 /lib/libc.so.6

On my 64-bit Ubuntu it needed to be:

sudo ln -s /lib/x86_64-linux-gnu/libc.so.6 /lib/libc.so.6

(i.e. the 64 bit library is below /lib, not /lib64)