Oh god for crying out loud...didn't you guys already know that there are problems installing scripts with Vista?
After all here are other threads like this one:
http://shoutbox.menthix.net/showthread.php?tid=71855
http://shoutbox.menthix.net/showthread.php?tid=71828
I know Dazmo is using a BETA2 version but a similar thing would occur. And yes it should be fixed in 4.20