WMP11 Spanning Problem

I'm running WMP11 on Vista Ultimate. I want to burn a library which takes
three discs. After the first is done, I'm prompted to insert a second CD,
which I do, and, nothing happens. How do I tell it to start writing the
second (and subsequent) CDs?

Note if I hit Start Burn in WMP11, it starts over again to write the first
disc.

And note when I insert the second CD the Autoplay window opens. If in that
window I hit burn files to disc, it wants to prepare a blank disc, and if I
hit that it says another program is using the drive. Do I need to disable
Autoplay?