Aha same issue as on XBian.
Try below one:
sudo ln -s /lib/arm-linux-gnueabihf/ld-linux.so.3 /lib/ld-linux.so.3
Start here up with:
sudo /etc/init.d/pihole-FTL restart
If the symlinking fails because file not exist, search if you've already got it installed with:
sudo dpkg -S ld-linux.so.3
Use the location of the file displayed as replacement for the symlink command eg:
sudo ln -s /some/lib/location/ld-linux.so.3 /lib/ld-linux.so.3