This bug appears when try to install the program by setup.exe, previously unpacked it by any archiver. After launching the installer, accepting EULA and typing personal data, when try to click on the button for the third time, nothing happens. See bug.webm and debug.log
P.S.: this issue also is present in Microsoft Virtual PC 2007 SP1 installer, which can be downloaded here: https://www.microsoft.com/en-us/download/confirmation.aspx?id=4580&6B49FDFB-8E5B-4B07-BC31-15695C5A2143=1
And in w2k3 it works correctly.