web problem with contactform7

Hello:
When I use this form

Call for Papers and Poster Presentations Form

to upload a word doc using the form submission, it fails.
WE NEED THAT TO WORK

WE NEED ANSWERS TO THESE THREE CARDINAL QUESTIONS:

1) Why is it not working?
2) Can you fix it?
3) If fixed, HOW was it fixed?

Here are the word docs to test with, a large one and a small one:

this one:

Test-Small-Upload-Size

and this:

Test-Upload-Size-SixPointFour-MegaBytes