Remember the files are not actually physically sent to iTunes. iTunes makes a playlist called LimeWire, but the actual files remain in the LW download folder.

Open iTunes, Go to Edit menu > Preferences > Sharing & check option to share .. the first one from memory.

Open LW, go to menu bar, Tools > Options > iTunes > Sharing & check option for sharing & put in a name of your choice. Press apply.

If still doesn't work, go to Tools > Options > Player & disable LW's media player.