I got it working last night!! I had gotten Windowed
You can't open the demo files from the Program files directory because Windows locks the directory. Moving the demo files to your desktop/documents folder and everything works.
For those of you playing along at home here are my Windows install steps.
I couldn't use the Addon manager inside of FreeCad due to it flagging the missing libraries.
So I downloaded the package from the github repository. https://github.com/jmplonka/InventorLoader
1. Browse to C:\Program files\"FreeCad Version"\Bin\ Create a folder called MOD under the Bin folder.
2. Extract the files downloaded to the newly created MOD Folder.
3. Extract the libs.zip to a folder called libs inside the MOD folder.
3. Launch Command prompt. Remember to launch Command prompt as ADMINISTRATOR (Thank you Windows)
4. In Command Prompt type (adjust FC bin path accordingly): PATH="C:\Program files\FreeCAD\bin";%PATH%
5. Set Command Prompt to the newly created libs directory C:\Program Files\"FreeCad Version"\Bin\MOD\libs
6. In Command Prompt type: cd olefile
7. In Command Prompt type: python setup.py install
8. In Command Prompt type: cd ..\xlrd-1.1.0
9. In Command Prompt type: python setup.py install
10. In Command Prompt type: cd ..\xlutils-2.0.0
11. In Command Prompt type: python setup.py install
12. In Command Prompt type: cd ..\xlwt-1.3.0
13. In Command Prompt type: python setup.py install
14. Exit Command Prompt
15. In Windows Explorer browse to C:\Program Files\"FreeCad Version"\Bin\MOD and copy the Demo-Status folder to your desktop or your documents folder.
16. Reopen FreeCAD and browse to the new location of the Demo-Status folder and select and ipt file to open and test.
If this doesn't work turn on the Report View under View--> Panels--> Report View so that you can see the full error message.
I hope this helps someone.
Thanks to Jens for the awesome plugin.