I was just trying to install SCVMM 2008 Beta 1 today. When installing the SCVMM 2008 Server, it failed installing the WAIK prerequisite asking me to instead install this manually.

Attempting to run the WAIK msi directly from the prerequisites folder (\prerequisites\WAIK\1033) failed asking me to "Insert the WAIK setup CD". I think this problem might be caused because I'm install SCVMM 2008 from a DVD. I copied the files from that folder onto the hard disk of the machine, and then attempted to run the MSI again, and WAIK installed successfully.