When you install Final Cut Studio from the DVD, the Installer does not properly check the amount of free disk space available on your computer before performing the installation. You will need 4 GB of disk space available to install all the applications; you will need an additional 41 GB to install all optional templates, loops, content, and tutorials (these may be installed on separate disks).
If your computer does not have enough available disk space, the Install button in the Installer will still be accessible (it won't dim), allowing you to start the installation. If you do so, you'll get the following error during the installation process:
"Your startup disk is almost full"
A few minutes later, a second dialog will appear:
"There were errors installing the software. Please try again."
If you see these errors, you can free up some disk space by throwing away files and applications that you no longer need, and backing up files that you wish to keep to other volumes or media. You can also custom install only specific parts of Final Cut Studio and you can change the location for certain items. See the Installing Your Software guide for additional information.