can no longer sync iphone photos with iphoto on my mac

My iphone has stopped syncing photos taken on my iphone when I sync on my mac, and I can't find a way to fix this. All help greatly welcome.
My iphone is running on software version 3.1.3 and my iphoto software is running version 8.1.2
Anyone know how to fix this?
Many thanks, Lorien

Does anyone else have this problem?

Just wondering if anyone else has this problem and how to solve?