Install the Primstar scripts in the .blender/scripts folder.
If the .blender folder doesn't appear to be there, you need to change your OS settings so that hidden files and folders are shown.
Domino's Primstar Scripts
Download the scripts from here.
Installing the Primstar scripts is probably the most troublesome of the three.
Go into your file explorer, and navigate to the Blender data directory. You're looking for the .blender/scripts folder.
.blender is a "hidden folder." If you can't see it, you may need to change your settings to show hidden files and folders.
In the Windows file explorer, go to Tools > Folder Options, and in the View tab check "show hidden files and folders.
In the Mac OSX, type the following in the Terminal:
defaults write com.apple.finder AppleShowAllFiles TRUE
killall Finder
Try looking for the folder in the following directories:
Linux: ~/.blender/scripts
Mac: /Applications/blender/blender.app/Contents/MacOS/.blender/scripts/
Windows XP: c:\Program Files\Blender Foundation\Blender\.blender\scripts
Windows Vista: C:\Users\USERNAME\AppData\Roaming\Blender Foundation\Blender\.blender\scripts
Once you've found the scripts directory, drag the entire Primstar scripts folder into the scripts directory. If you've installed Domino's scripts previously, you might have to find the old ones and delete them manually. Now you're ready to start Blender.