The option of auto-adding songs from LW to iTunes which was introduced for Windows users in LW 5 suffers same problem Mac OSX users have had for a number of years with LW. Sometimes LW is very busy or during a long session, iTunes stops importing. Answer is to either restart LW, else another good process is go to the options, disable iTunes adding, press OK. Close option. Then return & re-enable it again. This will usually fix things.

Oh Birdy said that. lol