Notebooks for iPhone Answers

Any clue how I can restore my lost data? I tried to download the new version update today and got a gray box that said waiting. Then when I logged into iTunes on my computer I updated to the new version. When it synced to my iPod Touch all my pdf, notes and notebooks were gone. Is the information still on my iPod and is there any way to access it? I tried deleting ver. 4.0 and going back to 3.2.3 but even with the old version of the program everything is still gone.

Thanks,
Jared