I have just reloaded an SBS 2003 installation from a backup after a hardware failure of the motherboard. I got an error in the Application event log that told me that license usage was nearing the maximum, so I went to check the licensing MMC to see that my CALs were there after the restore. What I found instead is that when I launched the Licensing MMC from the Administrative Tools window, I got the error in the MMC console that "MMC could not create the snap-in."
Based on other ideas that I'd found on the net, I tried both uninstalling/reinstalling the .net framework and I tried to download and install the Adminpak.msi (both locally on the server console and on my management workstation which is a Windows XP SP3 system). The licensing MMC for SBS isn't a part of the Adminpak anyway, and the adminpak would not load on the SBS 2003 console, so that got me nowhere.
I'm open to suggestions for a next step ... let me know if any more information is needed. It's an SBS 2003 server, SP2.