Sorry, but just to be sure I understand, here's the sequence I use:
1. click the "Burn Disc" icon in the lower left action window
2. the "Burn Disc" action window shows with "Audio CD" selected in the drop box
3. I click the "Next>" button
4. the "drop here" graphic shows in the action window
5. I drag a couple audio tracks onto that area and this appears:
6. I click the Burn button and this dialog pops up:
I'm assuming step #6 is where you are seeing a different message, is that right?