Remote Installation Service and SP1/SP4

Urgent help needed.

I tried to save an image to my RIS server and got the following error message “Missing CD Image on Server–The server to which you chose to replicate this system does not contaon a CD-based image. The version of the CD-based image on the server must match the version of the system you are attempting to copy. Select a different server or add a CD-based image to this server”.

The only thing I think could cause this is that the original (basic 2000 pro image I put on the server was service pack1 and the image I am trying to save now is service pack4.
How do i incorporate a SP into the original image or compile it into the installatiom media.

I am running a Windows 2000 domain and I am able to save images with SP1 onto this server.