Mac Migration Assistant Compatibility
When using the Mac Migration Assistant and migrating from an older Mac running 10.5 Leopard to a new Mac running 10.9 Mavericks, you won't be able to use a wireless network migration and instead need to use another type of connection (a migration where the older Mac is in Target Disk Mode will work).
When you first setup a new Mac, you're offered the chance to use the Migration Assistant to copy files from an older Mac. You can connect the two Macs using many different methods, outlined on various support pages on Apple's website.
If you're trying to upgrade from an old Mac (in my case, it was a Mac running 10.5 Leopard) to a new Mac running 10.9 Mavericks, only some forms of migration will work. In particular, a network migration (wired or wireless) will not work as the Migration Assistant will error on the new Mac saying that the old Mac must be upgraded to the latest System Software.
However, if you connect the two Macs directly using Firewire and/or Thunderbolt while the old Mac is in Target Disk Mode, you will be able to complete this migration without error.