there are a couple of things you can do.
1>go back to fry's and explain your problem, maybe they will help or have another bad processor and they can give you another button.
2>can the buttons all together and mount the heatsink without them, we did it that way until they came out with the buttons, and get a non conductive shim and put it between your processor and heatsink, they are available all over the web, helps to keep her level.
3>move the remaining three buttons and configure them in an equalateral triangle (hope you know what this means) on the CPU, that way the pressure will be distributed evenly again and that should work, just make sure that the buttons touch the heatsink properly and that the buttons are also not sitting on anything else that may fubar the height.
good luck.
baldy