Tailgate Won't Open

My wife has a 2000 Grand Vitara and a couple of weeks ago her tailgate won't open. At first it would open once in a while, but now it won't open at all. It feels like the handle to open the door is stuck or not catching the lock or something. I don't know how to fix this. Does anyone have any suggestions?
Also right about the same time the driver's side back seat door won't open from the inside. So if you were sitting behind the driver you won't be able to get out unless the driver opens the door from the outside. The handle feels like there is nothing attached to it. Is this something I need to take in to get fixed or can I fix it if I take the door panel off?

Thank You

For the passanger door. Those handles are pretty fragile. My mos owns a 2002 Vitara. I had to replace the handles on both sides. That's somthing you can do in about five minutes. All you need is a phillips screwdriver and don't try to force the metal clabe/thingy buy pulling on it just leave it as is you have about 1/2 to 1/4 inch of cable visible. Then you just need to fit in. with practice I gets very eassy. As for the tail gate my advice is pull the panel of and see what's going on. It's probably that the handle broke.