Well, LW (and for that matter, any other p2p softwares) wouldn't recognize files without the file format identified (e.g. .mp3, .jpg, .sit etc...). But it seems your files have them already, so it must be something else.

I wonder how you added your 10 gigs to your sharing list.
The "usual way" is:
1. Start up LW
2. Go to Tools<Options<Sharing
3. Click "Add..." (a new window will open)
4. Select the folder(s) you want to share, and click OK (or Apply).
When you've done this, you are sharing not only the files you downloaded, but also all the files which are in the folder(s) which you've just registered.

Alternatively, as you seem to have done, you could drag the folders you want to share into "Shared" folder in which the newly downloaded files move in.

Now, the way to confirm whether the files are actually shared:
1. Open "Library" window (after starting up LW of course)
2. Look at the colum on your left (it should at least have "Shared" and "Incomplete" folders)
3a. If you share your files "the usual way", you should see the folder(s) which you've just added.
3b. If you moved the 10 gigs into the "Shared" folder, then open the "Shared" folder until you find the folders you moved. If you see them, you've just made LW community 10 gigs wealthier.

If you still don't find the folders which you moved into "Shared" folder, go back to Tools>Options>Sharing, and see if the "Shared" folder is indeed listed there. It could be either that LW somehow has not included the "Shared" folder on the list there, OR that you've somehow moved to a folder named "Shared" but in fact is a different folder which is listed on the preferences (this happened to me once).

Have another look, and let us know how it's going.