I tried to update my iphone 4 but it keeps saying error (1667) what does that mean?

I had the same issue, changing the USB port on my mac strangely solved the problem

None of my 4 or 4Ss are updating yet. Iphone 5s and new iPad did...

http://lmgtfy.com/?q=iPhone+error+code+1667

I had the same problem

and I solved it by uninstalling iTunes and then installing it again

put your iphone on recovery mood and try again