So you are getting an iTunes alert "The iPhone cannot be synced because of unknown error occurred (-50)"

Unfortunately errors like this make me feel like I am using a PC. I can't imagine it would be that hard for Apple to translate these cryptic messages into human readable alerts that inform us what the problem is and how to fix it.

That being said, here is the likely problem:
iTunes is having problems syncing your photos from iPhoto. There are a few possible reasons for this. Unfortunately, none of the solutions are for the faint of heart. Please give us a call. (514) 836-7831