Boolean (difference) not working properly on rather simple geometry This topic seems to be asked a lot.
I am very new to blender, so I am still learning the in's and out's. I am trying to use the small cube to cut out a section of the latch, however, each attempt instead removes the latch and leaves the cube. I have tried the three recommended solutions of eliminating duplicate vertices, recalculating the normals, and making sure the geometry is all closed up. Still, even with those checks, when I try to use the boolean difference modifier, it doesn't work properly.
dropbox file

http://i.imgur.com/5ySnVQx.png
Make Sure all the Scale values of the Smaller Simple Block are Positive ... greater than zero.

The scale values should all be positive.  Remove the negative sign.

The smaller item in the picture needs to have all scales positive for clarity and to have the boolean modifier work.

Here are suggested settings for the modifier.