This version has been built using Mac OS X 10.9 (mavericks) on x86_64. If you want a universal (i686 + x86_64) binary that works with older versions of Mac OS X, please use the older version.
This version includes a switch to Objective-C ARC, which resolves issue #1.
To install, unpack the ZIP file (QCQREncoder-mavericks_x86_64-1.1.zip) and put QCQREncoder.plugin in ~/Library/Graphics/Quartz Composer Plug-Ins/.
Once this is done, you can use Quartz Composer to design compositions. You may wish to look at the QR-Clock.qtx file in the GitHub repository for an example. You won't be able to open that in the (default) QuickTime Player, but you can use it as a Screen Saver if you don't have Quartz Composer installed.