How can I make Flash Builder 4 launch browser on run?

I recently installed Adobe Flash Builder 4 in standalone mode on a new installation of Windows 7 x64.

I can load and build an existing Flex 4.1 project I have been working on, but when I go to run the project in the browser (Firefox 3.6.15), I get:

'Launching BensApp' has encountered a problem.

An internal error occurred during: 'Launching BensApp'

Clicking the Details >> button reveals:

java.lang.NullPointerException

My project is creating the SWF and container HTML page as expected, but fails to load the b开发者_JS百科rowser.

Ok. Finally nutted this out.

The problem was that Flash Builder was trying to run the ASP.NET web server at:

c:\Program Files (x86)\Microsoft Shared\9.0\WebDevServer.exe

This is the default location if you have VS2008 installed.

I only have VS2010 installed, which places these files at ...\Shared\10.0. The solution was to copy WebDevServer20.exe to the above location.

The other solution that would work is to change Flex Server \ Application Server type to "None\Other".

Check the launch configurations located in Project>Properties>Run/Debug Settings.

To open a browser when you run the project you will need to modify the 'URL or path to launch' parameter.

See the Adobe Flex help for more info: Managing Launch Configurations.

Select "Run As" in Green Debug Button. It Fixed My Problem.