iPhone 5 won't backup to laptop because not enough space but I have 400GB

I ran into this problem before and ignored it and somehow it dissapeared. But now it's returned after the latest iTunes 11.0 update. I have an iPhone 5 and I'm syncing it to a macbook running 10.6.8

Everytime I sync the phone it gives me this error "iTunes could not backup the iPhone because not enough free space is available on this computer" it suggests that I delete and empty some files. However, I have 459GB available. And it's only a 16GB phone.

I've tried re-installing iTunes, restarting both the laptop and the iPhone, and running disk utility. I've also deleted all the songs from the phone and it didn't fix the problem. Anyone has any idea?

Thanks!