Cannot deploy a ClickOnce Application to Windows 2000 machines with CR 2008

I just want to verify this and if its true figure out why and a way around it. I have a Visual Studio 2008 application that is deployed through ClickOnce. We recently upgraded to Crystal Reports 2008 because CR XI R2 wouldn't integrate with VS 2008, also because the sales literature said it was a smaller footprint on the client machines for the runtime (which turned out to be true, 240Mb on XI down to 140 on 08).. We have about 90% XP machines and 10% are still Windows 2000 Pro. The last deployment failed on the 2000 machines with a cryptic error message and it looks as though the runtimes will not install on Windows 2000. Is this true? If so why? Is there a way around that?

-Allan