Can't add Main Menu to "Theme locations"

Hi,

I just added new plugin – “User profile made easy” to my Highend theme and it crashed.
1. New plugin required php version 5.3+ for some date calculation or something… and i updated my php from 5.2 to 5.4. And now it seems i lost some pages in my mane menu which i created earlier and i can’t add main menu to the theme location. When i check the radio button and press save it doesn’t save it when a have already added new registration page made by newly added plugin – “User profile made easy”.

Can you help ?
Thanks
George