While working with SharePoint and Commerce Server 2009 , to create web application using SharePoint Commerce Configuration wizard , you run wizard and enter all required fields like port , host header , extended site port , host header and click ok .. What happens? (at least happened with me)
Error: Web Application creation failed. Check the logs for details
Why?
This error occurs If you trying to create your web application and extended site on same port
So obviously workaround is, change the port number of web application and of extended site
Here is Kb article which explains about this error
This worked for me atleast J , and hope this helps some one