I have just downloaded the onavo extend app which apparantly compresses data so you get more out of your data plan.
Anyway, I have installed the actual profile on my phone but it says profile not installed correctly. then gives an option to try again. i must hav done this about 4 times but its still not installed.
Are you on WiFi when you open the app? Onavo Extend compresses 3G and 4G data, so will let you know that there is an error if you are on WiFi, because it won't compress that data.