Error Using PerformancePoint 2007 Dashboard Designer

While setting up my SQL Server 2008 RTM image, I needed to create a demo using PerformancePoint. 

After installing PerformancePoint (by the way, I had to point it to a SQL Server 2005 instance for it’s own databases, it didn’t like 2008)  I went to connect to an Analysis Services 2008 data source.  I got an error, something about data source not found.  I wasn;t sure if this was going to be a problen with 2008 cubes in general.

After some investigation, I realised the problem was not with connecting to SQL Server, but rather PerfPoints own web service.  In IE, I browsed to http://localhost/WebService/PmService.asmx. There was an error message “could not system.web.extension version=1.0.61025.0.“

A couple of articles talked about some workarounds,

http://nickbarclay.blogspot.com/2007/11/pps-data-source-connection-problems.html

http://hassansyed.blogspot.com/2008/02/ms-performance-point-connection-issue.html

But they looked like a bit too much hard work.   So I tried installing ASP.NET Ajax 1.0 from