I have Pages from iWork '06, '08 & '09 & don't have any problems but I have seen others mention this issue.
If you reinstalled iWork '08 from the original disks & haven't run Software Update to get the most recent version, that would likely be the problem, especially if you are using Snow Leopard. Many users are finding problems with the iWork apps in Snow Leopard due to not having the latest updates as of the September 28 installed. For iWork '08 that is Pages 3.0.3 & Numbers 1.0.3. For iWork '09 it's Pages 4.0.2 & Numbers 2.0.2. iWork '09 has since had update 3. I don't use Keynote, but it should also be updated. If you're not running the latest versions & Software Update says your software is up to date, make sure the applications are where the installer initially put them. The updaters are very picky. If the location is not where the updater is programmed to look or if the folder doesn't have the name the updater looks for, it will not work. The applications cannot be renamed or moved. They must be in the iWork '08 or iWork '09 folder in Applications. That iWork folder must be named iWork '08 or iWork '09. If it doesn't have the '08 or '09 Software Update won't find them & the updaters won't work.
