Itunes iPhoto Sync doesn't work

I have been syncing photos from iPhoto onto my 3GS 32GB iPhone and my wifes 16GB iPhones, using iTunes, for a while now. All of a sudden I was getting the following message pop up at the end of the sync and no photos had sync'd

[The iPod "name" cannot be synced. The required file cannot be found]

Short of trying almost everything to fix this I finally came across the solution.

1. Open up finder and navigate to the "iPhoto Library" package
2. Right click and choose "show package contents"
3. Delete the ipod cache folders

It seems that they had become corrupt and this was causing the issue.

Now all syncs fine again.

Update: another issue with photos not syncing is that they are removed by default if you are syncing video/audio etc, that is larger than the capacity of free memory left on the device.