I've seen this problem before, it is usually a sign that a hard drive is beginning to fail. This particular sound/problem usually occured on Western Digital hard disks, and it's looking like you have the second symptom in the form of a file that has become corrupt due to a bad sector appearing on the disk platter. You can try running Scandisk, (if you have it, any other disk scanner would work, just be sure to have it check the disk surface), and seeing how many bad sectors it finds. A typical pattern would be it will find, and fix bad sectors, but then more will appear later.
Some drives failing this way would just fail to boot, perhaps a sign that the first bad clusters occured on the boot sector. Other drives would just randomly go into that clicking sound, but it would get worse over time, until the drive eventually failed to boot.
Again, I've only ever heard Western Digital drives fail this way. That doesn't mean no other drive could fail that way, but if your drive is a Western Digital, I wouldn't be surprised.