DirectRT Beta - Error 1609

[FONT=Arial][SIZE=3][COLOR=Black]Hi,

[/COLOR][/SIZE][/FONT] [FONT=Arial][SIZE=3][COLOR=Black]A PhD student tried to install DirectRT beta on Windows Vista, but a window with an error message pops up (please see attachment).
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To install the DirectRT she followed your instructions, selecting the 2008 version when asked.
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Can you please advise?[/COLOR][/SIZE][/FONT][FONT=Arial][SIZE=3][COLOR=Black]
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Thanks in advance,

Simone[/COLOR][/SIZE][/FONT]