Thank you for getting back to us.
We have tested the installation package of the Sitefinity 4.0 SDK before the release, we have also tested this after you have reported your issue, still unable to reproduce it. We have tested on Windows Server 2008 SP2 with Windows Installer version 4.5.6001.22159 as in attached image. You can check the version of the installer runtime by running msiexec.exe.
the Telerik team
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