Yeah, it's leaking. What you see is tracer dye in the refrigerant oil.
You'd need a vacuum pump at a minimum to do it yourself, plus the receiver/dryer should be replaced whenever the system is opened. If you take it in you will have the cost of a new line, the receiver/dryer and a recharge. I have 609 certification and I do my own work, so I don't know what it costs to take it in. You might look up that line and the receiver/dryer on Rock Auto to get an idea of the cost, and call around for what an evacuation and recharge costs in your area. If both ends of the line are easy to reach the labor cost shouldn't be more than an hour.
5 years is pretty quick for the line to start leaking though. Too bad it isn't still under warranty.