Packages with pre and post scripts, etc

There are some packages that will not work in this script - ones that rely on a a pre or post script, for instance, or ones that demand that they be installed to an active system volume. For example (and it's possible that this is just me), it seems to me that when I put in the pkg for the latest version of Quicktime, it fails. Has anyone else run into this? I don't know that this is even something that can be 'repaired', but I'm curious if anyone has any good tests for checking if a script will be compliant. I'm thinking I'll just have to take some of these and have them intall after the frist boot of the machine.