Layout change causes photos to be discarded

Question

I love having a book making tool built right into Lightroom and Adobe has done a commendable job on the first release of the Book module. So far the interface has generally worked well for me. However...
Try this: Start with an auto-layout with 3 photos per page. Then, change one of the pages from 3 photos to 2 photos per page... Where did one of your photos go? Upon  investigation, you'll notice that Lightroom randomly picks one of your photos to discard and does not place it in a new page or anywhere useful. It just gets dropped without a trace! Unless you're very aware of what is going on, you could quickly make a book with many missing photos.
This could be better handled in a number of ways, for example by automatically adding a new page for the dropped photo, or floating the dropped photo in the grey area outside of the page. In fact, the grey area could be very useful as a "working area" for shuffling photos around by drag & drop. Additionally, an animation could be used to show what's happening when the layout changes and a photo gets bumped off.
Also, and perhaps this is a bug - sometimes when changing from a 3-photo layout that only has 2 active photos to a 2-photo layout,  the second photo gets bumped off even though there's an available spot for it in the new layout. The layout engine appears to sometimes prioritize the empty photo area over an actual photo - not good! I've also had instances when a photo get dropped when changing from a 3-photo layout to a different 3-photo layout. Very frustrating.
The photo usage count in the filmstrip is sort of helpful to find  photos that were discarded but in my opinion, too disconnected from the layout area to make for a seamless working experience. As a side note, it should be possible in the filmstrip to locate where a photo is used in the book and vice versa.
Other than this, the Book module is a great start at book making from Adobe.
Tom

Answer 1

Marcin
Welcome to the Apple Discussions.
Your issue seems to be with the underlying file system, not with iPhoto.
Some background:
Events in the iPhoto Window correspond exactly with the Folders in the Originals Folder in the iPhoto Library package file (Right click on it in the Pictures Folder -> Show Package Contents).
You can move photos between Events, you can rename Events, edit them, create them, as long as you do it via the iPhoto Window. Check out the Info Pane (wee 'i', lower left) the name and date fields are editable. Edit a Event Name using the Info Pane, the Event Folder in iPhoto Library/Originals will also have the new name.
When you move files between Events they are also moved on the HD.
Couldn't convert path /Users/dominika/Pictures/iPhoto Library/Originals/2001/Inne/070_RockyNeckCT14.jpg" to an FSRef to put on the pasteboard.
means that, for some reason, the file system is unable to execute that move. (That's the reference to the FSRef). However, iPhoto thinks the file was moved, hence the !.
I've simply never seen this issue reported here before. Is everything else on your Mac working correctly?
First off:
Check your HD for errors with Disk Utility, see if that reports anything.
Regards
TD