Iphoto 9.1.5 upgrade problem on July 12 2011 on iMac running Snow Leopard

Question

2nd user (My wife) on my iMac, following the upgrade today, when opening iphoto gave an error message of "Your photo library is either in use by another application or has become unreadable.  Shut down and restart your computer, and then open iPhoto again.  If the problem persists, try rebuilding your photo library.  To do this, quit iPhoto, and then reopen. it while keeping the option and Command keys pressed.  You can also try restoring your photo library from a backup" .
I followed these instructions and eventually selected the "repair" option, which was the first option.  This process "Upgrading Library: Scanning Library" has now been running for 2 hours and I'm concerned that it will not succeed. 
Secondly, since applying the complete upgrade to the ilife programs today, my network changed itself somehow from the network I had set up on my Time Capsule, to the network provided by my ISP.  How?  It had not been modified by myself and in fact a Time Machine backup to my Time Capsule was actioned successfully approx. 1 hour before the update was downloaded, via my Time Capsule Network and applied.  Nothing had been changed.
This upgrade has concerned me.  I've not experienced anything like this before with previous upgrades.

Answer 1

I ran into the same problem.  Installed 9.1.5 and BAM! - iPhoto wouldn't launch - got the "Your photo libary is either in use ..." error.  I did the normal stuff - restored 9.1.3 from my backup.  No dice.  Deleted iPhoto and reinstalled from origial media, then upgraded to 9.1.3.  No dice.  Reverted my iPhoto library to pre-9.1.5 date.  No dice.
So, I do a little digging.  I created a new library and that worked fine.  So, there's something wrong with my old library.  I showed the contents of the old library and the new one.  I looked at the files that were being modified at the time the library was opened.  There is a file called iPhotoLock.data.  Hmm.  I wonder ...
So, I deleted that file from the contents of the library (copied it to another location), opened iPhoto with the option key held down, selected my old library and it opened right up.
Short story is, the iPhotoLock.data file was corrupted somehow, so by deleting it and letting iPhoto create a new one, I was able to get all my stuff back.  Didn't have to use the library manager or anything that extreme.
I've seen a number of posts like this one and never saw an answer that was acceptable.  The only posts with an "answer" were to use the library manager to build a new library from the old one.  I loose things that way (books, etc.) and that wasn't acceptable.  I thought I'd post this so maybe others can try it and see if it works for them.
The explanation of how to do this is simple.  Open the folder where your library resides, control-click the iPhoto library and select "show contents".  You'll see the iPhotoLock.data file.  Delete it.  Close the window that opened when you selected "show contents".  Run iPhoto again and, if it works like mine did, your life will be back and visible again.
Hope this helps.
Message was edited by: Keith Cooley - spelling correction.