Lion Server: When creating a system image with added packages, OS X versions should match
In Lion Server v10.7.2 and later, you can use System Image Utility to add packages to a NetBoot or NetRestore image.
Lion Server, System Image Utility
When you do this, you should match (as closely as possible) the version of Lion you are running with the version of Lion on the image you are creating and the version of System Image Utility that you are using.
For example, if you are running OS X Lion v10.7.3, make sure that you use Server Admin Tools v10.7.3 and that you start with the OS X Lion v10.7.3 installer.
You can download the latest available Lion installer from the Mac App Store. If you have already purchased an earlier version of Lion, sign in to the Mac App Store using the Apple ID with which you purchased Lion, then hold the Option key while clicking on the Purchased tab. This will make the Install button active for OS X Lion active again.
A new version of the OS X Lion installer is usually posted to the Mac App Store shortly after a Lion software update is released.
In OS X Lion v10.7.2, you must match versions exactly. In later versions of Lion you do not have to be exact.