I set up an Exchange 2007 Edge Transport server recently, and when I tried to put my volume license key into the Edge Transport server, I was told that I had "attempted to perform an unauthorized operation."

This edge transport server sits behind my ISA server; inbound mail goes to it, then heads to my Exchange 2007 Hub Transport server for routing.  It has 1 internal NIC.

• Remote Registry service was enabled, and it was enabled on all GCs/PDCs/DCs
• TCP/IP was bound to all NICs (this one only had 1 NIC)
• I tried logging in as local admin and domain/enterprise admin

What worked?

Went into Active Directory Users and Computers on my GC.  Found the OU "Microsoft Exchange Security Groups" and the "Exchange Servers" security group therein.  I added the new Edge Transport server to this security group (since it wasn't a member!) and then restarted my Edge Transport server.

Key accepted.