Recently ran into some difficulty finding jetpack.exe on Windows 2008 server.  Eventually located the executable (thanks due to help from the technet forum - http://social.technet.microsoft.com/Forums/en-US/windowsserver2008r2general/thread/f4dcee02-18db-43b8-8af9-3c03b4011971). However, there are a few followup items that may be worth investigating. ( btw, I could not reply directly to the above thread as it is marked "readonly")

1) Why doesn't jetpack.exe exist in %systemroot%\system32\dhcp (or at least somewhere in the path) after installing the DHCP Server role on Windows Server 2008 and later operating systems?

In Windows Server 2008 and later operating systems, it's missing because it is only installed if you also install the WINS role.

2) Perhaps the source location of jetpack.exe and the steps to intall it on 2008 server should be documented somewhere official.

Below is the exact command I executed to obtain a copy in the dhcp directory where it is needed...ugly, but hey it worked!

C:\Windows\System32\dhcp>copy C:\Windows\winsxs\x86_microsoft-windows-jetpack_31bf3856ad364e35_6.0.6001.18000_none_5392e60e0965c1ce\jetpack.exe

The best solution to access jetpack.exe in Windows Server 2012 R2 is to install WIN Server role.

Tom