Welcome to the Apple Support Communities
Now, if you want to install iWork from the DVD, as your Mac hasn't got a DVD drive, you have two possibilities:
1. If you have another PC or Mac, use Remote Disc > http://support.apple.com/kb/ht1131
2. If you haven't got any other PC or Mac, buy an external optical drive and install iWork from there, or open App Store and purchase Keynote, Numbers and Pages as a download.
If you purchase the iWork apps again in the App Store, you will be able to install them in all your Macs as many times as you want for free, and you won't need any DVD drive to install those applications