This is not always the case & I'm not sure how I overcame it. Try reAdding your shared folders (take them off the list & reAdd.) Press apply each time & go back to your LW Library window & press refresh.

Also, depending on which iTunes folder is selected as the main share folder (for me it's called 'iTunes Music') (you better check it), if you click onto the folder's arrow in the LW Lib window, all its sub-folders (next level down) will show. For me that means a list of artists. Just click on the arrow next to any of them to see their albums. Next click on the album folder to see the songs listed in the window.