[AndreaAckhavong]

I've tried to click on the icon to open the application, but it does not open. The only thing that pops up is a notification saying "Mac OS update required. - iphoto requires Mac OS X version 10.7.2 or later. For information about upgrading your computer, visit www.apple.com/macosx."

[Big Mac]

Your photos are all safely stored even if you can't access them through iPhoto. But what version of OS X are you running?

[AndreaAckhavong]

Ok, good, but how would i find my photos again? Version 10.7

[OreoCookie]

Run Software Update to make sure you're running the latest version of OS X. Then try to launch iPhoto again.

[Doc HM]

iPhoto has some basic database recover tools.
First make a drag copy of the iPhoto library from inside your pictures folder onto either an external drive, or into another folder. That way you will always have a spare copy should things go runny.

Start iPhoto while holding the option key down to invoke the database repair utility at startup. Run the repairs and see where that gets you.

If you get no joy from that then you can drag the library out of the pictures folder to the trash (remember you have a spare) but don't delete it yet. Restart iPhoto which should now have a working (but empty) library.

Go to your spare library on the external (or wherever) drive and control click it and select show package contents. This will allow you to see the folders inside the library, where you will be able to see your original images which can be imported back into the new empty library.

Alternatively there is a great free app called iPhoto Library Manager from Fat cat software that will do this automatically AND keep all your album and meta data. Fat Cat Software - iPhoto Library Manager Help - Rebuilding a corrupted iPhoto library

[Spheric Harlot]

This is not a database issue.

The message that it requires 10.7.2 means that iPhoto itself will not open, not that it cannot read the database.

The original poster needs to upgrade to 10.7.2, or, if he already has, take steps to allow iPhoto to recognize it.

I would suggest (re-)installing only the 10.7.2 Combo Update from here:
OS X Lion Update 10.7.2 Client Combo

[Doc HM]

Originally Posted by Spheric Harlot 

This is not a database issue.

The message that it requires 10.7.2 means that iPhoto itself will not open, not that it cannot read the database.

oops. Did not read question properly fail!

[bugs]

You somehow got a version of iPhoto that doesn't belong with your Mac OS. Rather than buy Lion you might try to find the version of iPhoto that belongs with your system.

Still, you will discover that iPhoto (and iTunes) have a way of nesting your photos within many layers of sub folders making them very difficult to access without the original program.

I highly recommend Graphic Converter for people who's pictures are important to them. It's far cheaper than Photoshop yet gives you many options. And it saves files wherever you want them.