I would get ride of the variables to start with to make sure it is not the issue. You can always add them back in later once you have it working. Variables in LANDesk are also case sensitive and will not do anything if you dont reference them.
Do you have your image storage location (LDCore as per your screenshot)setup as a preferred server? This is how the deploy image action is able to connect to this location using the credentials you specify in the preferred server settings