I read all of the posts in this topic, and i saw, that the Stereo Tool has with Windows 7 problems, but i check the older versions with this new design and all of things works good, only the resize of GUI not. Now, i wanted to check the new design and i downloaded the BETA633-13 and BETA633-14 versions and i see only a white form with the name of window and the resize borders.

I hear the sound, what Stereo Tool processing, and the application starts normally in system tray. So, it is partially working, the GUI is not shown, and the icon in system tray is not view properly the volume levels.
I use Windows 7 64 bit version. I hope it helps.
What i saw in the previously versions of Stereo Tool is really beautifull.

So, i welcome the new GUI!

I had not read this, it's exactly the same problem that I have, renaming the file works fine.
Another problem is that there are times when you minimize the program, some things disappear and you have to change the size to return to show