There has been a recent bug where you cant light a nether portal with flint and tinder alone. What you can do now is put a dispenser with flint and tinder in it at the base of the nether portal you are trying to light and activate the dispenser with a redstone charge. Hope that helps. Cheers! ~Bean
Yea I had the same problem I figured that only admins can do it now because I had to have admin start my neihter portal for me in my town
You can use the following Dispenser as a substitute. Try not to trouble the Admins just to light something for you, they have a lot of things to do.
Items you need: 1 Dispenser , 1 Lever , 1 Flint n Steel . 1) Place the Dispenser down 1 block away from where you want your fire to be. 2) Put the lever on top of your dispenser by holding Shift + Left click 3) Place Flint n Steel inside the dispenser 4) Switch the Lever. Dispenser http://minecraft.gamepedia.com/Dispenser Lever http://minecraft.gamepedia.com/Lever Flint and Steel http://minecraft.gamepedia.com/Flint_and_Steel - Hope this helps.