what version of iPHoto was the old library created with? THe library upgraded is only required for iPhoto 7 and earlier -- http://support.apple.com/kb/DL1523
Every time I swithch to that old iPhoto Library and try to open one of the photos the page goes black except for a white exclamation mark inside white triangle.
That has nothing to do with upgrading or the upgrader - it is an indication of a broken link between the thumbnail and the original and is cause by one of two reasons -
1 - library corruption - fix by Back up your iPhoto library, Depress and hold the option (alt) and command keys and launch iPhoto - rebuild your iPhoto library database
2 - user actions that deleted or moved the originals - deleting using the finder - deleting from the all images list - using MacKeeper, cleanMyMac2 or other malwear that destroys the iPhoto library - if this is the dcase yoru only choice is to go to your backup from before the original were moved or deleted