I just added an album from my iTunes Music file to a Toast 6 window (in Leopard) and was unable to rearrange the songs with drag and drop.
I have Toast Titanium V6.1.1, running Snow Leopard V10.6.2. If it's helpful to this thread I just did a quick test.
I opened Toast, then opened iTunes. I dragged an album (Playlist) from iTunes to the Toast window and it loaded the songs almost immediately.
In Toast only the MP3 mode would not allow changing the order of the tunes. I was able to change with great facility in Audio CD, Enhanced Audio, and Mixed Mode.
ryck