Workflow problems in December CTP and WF :(

I just installed the Devember CTP of WinFX and it seems that I can not compile WF samples.  I had the Workflow Designer sample working just before the upgrade.  I had uninstalled everything (Nov CTP, WF 1.2, WinFX), then installed the latest WinFX runtime, Windows SDK, WinFX VS integration, WF 1.2 VS Integration.  Last night I worked on WPF and WCF and all was fine.  This evening, I tried a simple recompile of the Workflow Designer sample, and no luck.  It does not raise any events, warning or hints, just says "Build Failed".  Anybody else having this problem

Thanks,

Joe