says "Dev tools CTP must be removed first", even though I have removed it completely.
The log from the "Collect" tool is on skydrive:
http://cid-0f4bd79c5415e8f5.office.live.com/self.aspx/.Public/vslogs.cab
Answer 1
Try using this tool to clean up the old files, http://blogs.msdn.com/b/astebner/archive/2009/04/10/9544320.aspx
It has worked on both of my installs.