m able to log in but when i try to change the pvr capture card. it says "you are not authorized to modify installation."
My thoughts are...
You have multiple users in your LMCE setup?
Those users can have different security settings, including the ability to change the config (or not).
Sounds to me like the name you are logging in with doesn't have full access.
The one that should is the very first username you entered during the setup.
Look in Wizard > Basic Info > Users.
See if: "Master User (can modify configuration)?" is checked for the user in question.