A couple of days ago i posted this question.
http://forums.adobe.com/message/5485419#5485419
and for some reason i cannot put a reply on there, but i wanted to put a reply on there in case anyone else was having the same problem.
I tried lots of the suggestions that people suggested and i tried lots of other things too that i found via google... ie: changin permissions on my folders, installing on safe boot, uninstalling air and reinstalling it and nothing worked.
In the end i asked for help via the tech guys and spent a good few hours with one guy on chat who eventually took over my computer, and he was probably almost there but after nearly three hours, i had to go and deal with my children.
Then i started another chat with another tech guy (or gal, i don't want to be sexist) and he thought it was a problem with my colour profiles, so he asked me to run Terminal (searched for it via the spotlight search box) then i ran this command :
sudo mv /Library/ColorSync/Profiles/Profiles /Library/ColorSync/Profiles/Profiles_bkup
which removed the corrupt profile, and it now works.
so i hope that helps somebody else.
Charlie