When you install DVD Studio Pro (or the application as part of Final Cut Studio), the Installer progress bar may stop moving during the DVD Studio Pro 4 templates installation, reporting that the installation is 98-100 percent complete. Despite the appearance that the process has stalled, the installation is actually continuing.
Depending on the speed of the components in your computer, this part of the DVD Studio Pro or Final Cut Studio installation can take up to an hour to complete. If you force quit the Installer, the templates won't be correctly installed (if this happens, simply run the DVD Studio Pro Installer again).
If you would like confirmation that the Installer is still working, open Activity Monitor (find it in /Applications/Utilities) and inspect the Installer process.