The TDS protocol was originally limited to one statement handle per database connection. You can see the same issue with DBD::Sybase using the Sybase client.

Aha! This is the content that I was looking for.

And this is fine -- I just needed to really determine exactly what the limitation was, and then get my brain to suggest a workaround (not really a hack). And now I have it. Thanks to all who answered -- I appreciate you! If you're in Vegas next month, hit me up for a beer, and I will gladly buy. :)