No problem, glad to here that the tut is of some use to you. Regarding the background, it might be that the "Trees Outline" layer mask in the Channels dialogue is switched to visible. If there is a little "eye" icon floating to the left side of the layer mask, that means that the mask is visible. Just click on the eye icon to make the layer mask invisible and (if that really is the issue) the background should turn white again. As for the drop shadow, not sure why it didn't show up more. One other thing, the edges of the forest have a pretty noticeable bevel to them. This is due to the Bump map. I have not found a good way to get rid of the bevel except by simply covering it up with lots of "little" trees. If you read a bit further in this thread (I believe it's one of the updates on page 1) I explain how to do this.

Cheers,
-Arsheesh