The water supply for your fridge is usually made by connecting a plastic or copper hose to an existing water line underneath the kitchen sink. Follow the line from underneath the kitchen sink to the bottom of the fridge, or the back of the fridge, depending on where your water line connects to your Frigidaire. Inspect the hose for any signs of leaks.
Find the quick connect for the plastic hose where it connects to the fridge. Pull on the plastic hose with a pair of pliers at the rubber ring that holds it in place. To repair the hose, cut it back behind the leak and remove the damaged section. Slide the hose into quick connect coupling, which is available from most hardware stores. This is a quick repair that costs little.
Copper lines almost always require a full replacement because quick coupling for copper lines do not exists, and soldering thin copper used for refrigerators is difficult and could cause more damage than good if you are inexperienced with soldering. Unhook the copper wire from the fridge using a wrench to loosen the compression nut on each end. Pull out the old wire and take it to a plumbing store. They'll help you find the correct gauge and length for your replacement.
Loose compression nuts on the water valve can also cause leaks. Grip the valve with a wrench and turn the compression nut with another wrench to tighten any leaks. You might need to replace the valve if the leak continues even with a tightened compression nut in place. Remove the screws holding the valve bracket in place. Contact Frigidaire to find a replacement, or take the valve to a plumber to find a suitable part for replacement.