OS X won't boot. errno 19
What you may be able to try is running the fsck command in Single User Mode. As soon as you press the power button on your computer, press and hold Command+S until a terminal interface appears. When you see this: root:$ or something similar, type fsck -f and press enter. This will start a file system check which will most likely solve your problems. When it is finished, type reboot and press enter.

For my own curiosity, can you perhaps take a picture of the results? I'd be curious to see what it finds.