When I press the upload to put a pic onto facebook, the message "your photo cannot be uploaded [host is unresolved:api.facebook.com:80]" appears. Am I missing something?

^^^^ :d

I cant really help, other than to say that the message means that the app cannot convert that URL into an actual address.

This means that either your providers DNS isn't working. (the bit which converts the address into a numerical IP address)
Or the address is wrong (perhaps its changed and the app needs updating).
Or there is a temporary fault.
Or the phone is faulty.
Sorry I can't nail it down further.

Well that gives me a starting point to investigate! Cheers buddy.