Hi, Welcome to TSF :4-wave:
It could just be that you haven't set it to import correctly.
Press CTRL + , (or you could go to edit, then preferences)
Click on the Advanced tab
Click on the Importing sub tab
Change the import using to "AAC encoder" if it isn't set to that already.
Try importing in your songs again. If that doesn't work, try a different program to determine if the problem is with iTunes or the disk.
Hope this helps