Since you're not specifying the cPath parameter of extractPages it does not
return a Doc object, but null, according to the reference file.
Edit: My mistake, it's the other way around...
I've run your code and it seems to work fine (although it didn't go completely smoothly as I still had to manually allow the appliction to email the files).
Have you tried debugging it to see where the "Dead Object error" occurs?
Are you running Acrobat X in Windows? That's where I'm having the issue. It tested fine in Acrobat 8 in Windows.
I did do some debugging and once I removed that closeDoc call, the script ran fine, I just end up with a bunch of open docs. Everything else remained the same, so I assumed that was the source of the Dead Object error.
I had previously tried it in Acrobat Pro 8 and now also in Acrobat X. It seems to work in both versions.