"Pro Tools" could not be launched because of a shared library

Try this... Open Terminal.app and type:

sudo update_prebinding -force -root /
sudo periodic daily weekly monthly
sudo diskutil repairPermissions /

... and see if that helps. The first command updates the dynamic library cache (basically, an index of functions and the frameworks they're associated with). The second line invokes the regular maintenance scripts, and the last double checks that files installed as part of packages have the correct ownership and permissions set for them.

It sounds like a library/framework has been altered/updated/removed at some point.

The whole process will take ~10-15 minutes or so. There's no "done" message, you just get back to the shell prompt.

To make sure, you are installing version 6.9.2 or later of ProTools right? Previous versions don't work under Tiger. I think that the "DAE" part of the error probably refers to "Digidesign Audio Engine" which doesn't work with CoreAudio on Tiger.

No, the older PT won't run on Tiger (it installs fine, though).

That's how it should work. You can always contact the PT tech support to make sure.

The problem stems from the fact that the older ProTools is using a long since deprecated audio library. Newer versions use Apple's CoreAudio library. That's what the "DAE" in your error is referring to; the app can't run because it can't find the old audio support library (which no longer exists).