Transporter not found at path: /usr/local/itms/bin/iTMSTransporter. You should reinstall the application.
So I checked the path /Applications/Xcode.ap
/Applications/Xcode.ap
Basically what the above answer stated but the symlink command was wrong for me. I used the following command to fix it:
ln -s /Applications/Xcode.app/Contents/Applications/Application\ Loader.app/Contents/itms/ /usr/local/itms