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Emmanuel Desigaud's blog. Personnal, professional. Fun pictures, kewl web links, usefull software ....Sharepoint 2010 and Windows 2008 Web Edition
As soon as Sharepoint was available, I tried to install it on a virtual box running a fresh Windows 2008 Web Edition.
Got the following error : Application Server Role, Web Server (IIS) Role: configuration error
Based on log, it appears that the role "Application Server" is mandatory, and of course, this role is not available on Web Edition of windows 2008 Server so you must run at least Standard Edition, that's it !
Also, if you wonder changing your virtualization platform, before running to VMWare (which has poor performance for me), I advise you to look around VirtualBox (free, fast, x64 support, snapshot...)
Update :
Anyway, it seems that we can get around this limit by editing the installation files : http://msdn.microsoft.com/en-us/library/ee554869%28office.14%29.aspx