Surawut, I had some problems with the download link in your blog post, but was able to download the file from your Skydrive.
After installing, I was eager to test it out, but using the [Preview] and [Settings] buttons in the Screen Saver manager in Windows both result in instantaneous crash of the screensaver (e.g. the only thing that is displayed is the default Windows error message "PhotosynthSaver has stopped working. Windows is checking for a solution to the problem..."). I have both .NET 3 and Silverlight 3 installed on my Win7 RC (Build 7100) machine but no luck yet.
I also downloaded the RARed .scr from your Skydrive and tried executing it on its own, but experienced the same crashes.
Let me know if there's anything else I can tell you for troubleshooting. I'd love to try this out.