On this page you find further infos and support on installation problems an Mac which occasionally happen.
When the plugin is reported as "corrupted" after installation this may be due to wrong folder permissions.
Please open the "Library/Application Support/PPG/" folder in the Mac Finder.
Then open the Info dialog.
At the bottom you find a table with permissions for this folder.
Set the "everyone" row to "Read & Write".
Then install again.