Can you try the following:
1. Uninstall Stardraw AV Lite 2007 on your machine
2. Delete any left-over files from where you installed the software - usually C:\Program Files (x86)\Stardraw.com Ltd\Stardraw AV Lite 2007
3. Make sure you have all the latest windows updates installed for Vista 64 bit
4. Download and install a fresh installation program from: http://www.stardraw.com/downloads/2007/setup%20stardraw%20av%20lite%202007.exe
If this still fails to install for you, then please send an email to techsupport at stardraw dot com and we will arrange for someone to call you and try to diagnose your problem remotely. David SnippStardraw.com Ltd
In the last few minutes, we've just published updates to all our packages that are now certified for Windows 7 and therefore Windows Vista.
Please uninstall your current copy of Stardraw AV 2007 and download a fresh demo copy from our web site and let us know if you continue to have any problems. David SnippStardraw.com Ltd