My iPhoto will not open after restoring my iMac to original settings, please assist

Hi, I reset my iMac to its original settings. It's the aluminum 24" that was available 2 years ago. I just used the startup discs that came with it to wipe everything.
I extracted music, photos and applications I wanted to keep and saved them on my external harddrive and am now placing them where they belong on my clean iMac.

Problem is, I can't open iPhoto. It bounces a few times and the error message comes up. I have looked online for troubleshooting and tried things and it didn't work.

I don't fully understand what I did but this is what I did for troubleshooting:

I went to disk utility and performed "Repair Disc Permissions" and also tried to locate and delete the file "com.apple.iphoto.plist," in users/library/preferences but it actually does not seem to exist on my computer.
Then I checked the Console and I see repeatedly "Library not loaded" and "image not found"

What can I do? I don't know if I confused my iMac because I saved all my applications on my external harddrive and added them back to my iMac, not replacing ones already on my iMac. Retracing my steps that is all I have done, at least knowingly!

Please help me out, I appreciate it!

Why did you reinstall OS X? Were you having some problems that could not be resolved any other way? The reason I ask is that OS X almost never (unlike Windows) has to be reinstalled.

Also, if you're running Leopard, an "Archive and reinstall" would have been the proper way to reinstall as that will save all your user settings and applications. (Snow Leopard does that automatically.)

What you can try in order to get iPhoto working again is to do a separate install from your original DVD. And for that, you'll need software to extract it first. "Pacifist"