Smashwords are having some technical difficulties with the 100% off promotion code for Read an Ebook Week. While they are working on it, I've generated an additional code that can be used to purchase A Little Girl in my Room & Other Stories for free.
Type EF96D into the space provided before checking out and this Ebook will be free.
If there are any other books you would like to download for free but are having trouble with, just give it a few hours or try again tomorrow. I'm sure the issue will be sorted asap.