Some of us have had some issues with installing applications since the new installer was released.
Some app’s that simply refused to work without some minor adjustments.
I personally had the issue with customize and some other app’s.
I clarified released a fix for these issues, you can find the update in the installer.

The name of the package is Installer 3.1 fix

This little app is available in the Installer.app through the iClarified packaging source, see our sources page.

Enjoy

Don’t install this, just go for the updated version 3.11.