can't install xcode, issue with MobileDevice.pkg
I came across this issue in another post but not certain if the errors you are getting are the same but here it is. Source is provided below:

Use Pacifist to install MobileDevice.pkg!!!
Simply open the file with pacifist 
click the top right Lock button that says Not Authorized 
Type your password
and hit install
once thats done install itunes normally
or with pacifist worked great for me

SOURCE:
http://www.tonymacx86.com/general-help/98821-xcode-itunes-mobiledevice-pkg-fix.html