Take a look at your LW configuration.

Limewire has two different folder settings:

One for the shared folder - which is for the files that appear in the shared part of the library window and that other users can download. Acess this option by going to Tools=>Options=>Sharing.

The second is the save location, which is where the files you download are saved. This option can be found Tools=>Options=>Saving. Take note of this path since this is where your d/l files are going.

Make sure the two folder paths are the same (as they are by default), otherwise the files you download won't appear in the library window.

By default, the path for both of these options is: MyMac[the name of your HD]/System Folder/Preferences/Shared

Mine is in: MyMac/Applications/Limewire/Shared

Note: It's possible to have more than one shared folder (two or more paths will appear in the options , but all the files in will appear in the same shared library window). To avoid confusion I only have one.