Does it render normally on the local machine (no Backburner) when Targeted is unchecked, and Target Distance is set to 100 (and not when Target distance is 0)? Also, I presume something like depth of field is used (otherwise not sure Target Distance would affect anything) - if so, have you tried overriding the DOF Override focus, so it doesn't use the Target distance? Could enable you to continue to use untargeted cameras if you really prefer it that way :)