They were talking about the fire control computer on the weapon emplacement itself. It basically works the same way as a starship gunnery computer, or a scope on a rifle: it gives the operator a bonus on their attack rolls. Without knowing exactly what type of targeting system is in use, Mariah can't really do much from here.
If it is typical Imperial kit, it will have a visual processor combined with an or Laser rangefinder. To disrupt that, you'd been some sort of chaff cloud or smoke screen to break line of sight and disrupt the EM pulses. That's a tall order.
Your best bet at this point is to hope Trax takes out the uplink and gun quickly. And, since he's going to be firing an E-Web at them, it's likely they'll be distracted and may not notice the shuttle approaching until it is too late.
