iPhoto hangs up when trying to sync pictures from iphone

I used to be able to upload pictures from my iPhone 4 (Verizon) to iPhoto 6.0.6 with no problem. However, my most recent attempt to upload pictures failed after several attempts. The only thing that I recall being different since my last attempt is that I upgraded from iOS 4 to iOS 5.1.1. When I attempt to upload pictures, iPhoto appears to be uploading pictures, but it hangs up or crashes about 80% of the way through the process. FYI, I use the following verisions of relevant software:  Mac OS 10.6.8, iTunes 10.5.2, and iOS 5.1.1. Anyone have any solutions and know about incompatibility between my current versions of iPhoto and iOS software? 

Thanks,

Jeff