Steve,
I was able to open the file in LazyCAM 2.02 (the latest version that I'm still able to pocket in...) and clean up the file a little bit, then pocket the lower portion. Have a look and see if that is what you are want to do. I just pocketed the lower portion with a .25" cutter. I did not offset the drawing to cutter compensate so if you cut this file the CNC mill will follow the vectors as its toolpath. If you are using a very small cutter, or you cut with laser or plasma then no problems.
If you can, I recommend reverting to the July 2.02 version of LazyCAM. Others have had luck with 2.47 but I don't know what they are using it for... I do a lot of offsetiing and pocket milling. Hope this helps,
Shane