I'm "assuming" this is in DS 7.1, but you do need to specify this now that we have two VERY different releases and troubleshooting is very different.
Assuming this is DS 7.1, then you need to un-set the "hasSBSRegistered" registry key and cycle the services to force it to check in and become active.
Remember too that in 7.1 you MUST have package services on the box, and Task, or images wont download. In 7.5 this is a different issue, and you don't need to have the images there, because they'll be on the package servers. IF this is a package server, those images will be under the package agent, not DS agent - again, in 7.5
Finally, if you're worried about the preboot images (which I was not discussing in the above paragraph), then the system MUST be considered a PXE server (hence in that page) or bootwiz will never fire to build them.
So, there's a head-start. GL!!