Hey man I see this is a real old post but I am completely setting up my c-305 right now and that is not correct.
In each string saddle, the tiny Allen screw that faces the neck locks in the action height. That screw has to loosen before you actually turn the screws on top of the saddle to adjust the action, then you re-tighten and it locks.
The other screw, the one kind of underneath the string, locks in the intonation. Same deal, to push the saddle forward or backward, that screw first needs to be loosened.
If either of these do not engage, you most likely have:
A) stripped the screw
B) adjusted the action/intonation too many times without unlocking and now the screws have dug into the bridge itself and no longer work
Either way, it sounds like you might need to call ESP and get some parts.