Mac – How fix broken Macports installation after manual deletion of app

This problem sounds like you did not set up dbus yet. Read the output of the command port notes dbus and follow the instructions.

$ port notes dbus
dbus has the following notes:
  ############################################################################
  # Startup items have been generated that will aid in
  # starting dbus with launchd. They are disabled
  # by default. Execute the following command to start them,
  # and to cause them to launch at startup:
  #
  # sudo launchctl load -w /Library/LaunchDaemons/org.freedesktop.dbus-system.plist
  # launchctl load -w /Library/LaunchAgents/org.freedesktop.dbus-session.plist
  ############################################################################

Did you run sudo xcode-select -switch /Applications/Xcode.app? This message: error: can't exec '/Developer/usr/bin/xcodebuild' is telling you that your system is looking for xcodebuild in `/Developer/usr/bin/' but as of Xcode 4.3 (the one that's installed from the App Store) it's located in the Xcode.app bundle which is in /Applications.

Edit

In a comment to your question you say you've run sudo xcode-select -switch /Applications/Xcode.app. Now run xcode-select -print-path and make sure it says "/Applications/Xcode.app".

Also, you may need to download the command line tools separately. (I don't know from first-hand experience because I'm stuck on Snow Leopard for the moment so I haven't installed Xcode 4.3.)