You could try to solder the pin back on (if you still have it), or pry a pin off another AM2 processor (if you have another broken one) and put that on.
I doubt it'd work, but it might.
Sometimes the pin isn't important. Other times the pin is simply a VSS or VCC, and can easily be wire connected another VSS or VCC. Look up the AM2 pinout diagram to see what pin was affected.
It's related to why my Asus board would not post. Removed the processor (AM2 4600 65w) to ship the board back and found a number of pins bent and 1 broken after I tried to straighten out.
Now, when I installed the CPU, it just dropped in easily and I locked the ZIF? lever. The heat sink was tough to latch (some effort), and now I know why, the pins were being bent. I don't know how because of how easy the processor dropped into the socket.
The site I referenced used to fix for $20-$30, which is not bad but the darn site is down, not sure if the guy is out of business or just web glitch.