
If you have an iPhoto library that is corrupt and causing iPhoto to crash or otherwise be unusable, iPhoto Library Manager provides the ability to rebuild your library based on the information found in its AlbumData.xml file. Select the library you want to rebuild and choose the "Rebuild Library" command from the File menu. After choosing a location to store the rebuilt library, iPhoto Library Manager will proceed to try rebuilding the library as best as it can based on the available data.
Note that iPhoto also has a built-in rebuild function that can be sometimes be used to repair a corrupted library database. You can find instructions on how to use that on Apple's website at http://support.apple.com/kb/HT2638 (iPhoto 6 or later) or http://support.apple.com/kb/HT2042 (iPhoto 5 or earlier). iPhoto Library Manager's rebuild works differently, in that instead of trying to repair the library in-place, it instead creates a brand new library and tries to reimport the entire contents of the original library into the new one, including reconstructing albums, photo metadata, etc. Note that rebuilding a library has all the same limitations as other photo transfer operations as far as what can and can't be copied between libraries.
If neither iPhoto nor iPhoto Library Manager can successfully rebuild your library, your best bet is probably to use the Extract Photos function of iPhoto Library Manager instead. This will not retrieve any of your iPhoto specific data (i.e. albums, keywords, etc.), but it should at least allow you to retrieve your photos so that you can start a fresh library and import your photos back into iPhoto that way.