Jeff....That's what I did but it still didn't come up under Automate or Filters. So, I installed it in CS5 and changed CS5 to 32 bit Mode and it worked in CS5. I therefore believe it is a 32 bit app and will not work in CS6, unless I missed something somewhere.
Thanks for all the responses. Just trying to find an easier way to do blending of two images (Over/Under Exposure) especially when there are trees or branches from plants which are difficult to do a selection around. If anyone has found the "magic bullet" solution I would love to hear about it.