Flint and Steel wont work

The other day I was on my server and tried to use flint and steel to make a netherportal but it didnt work. So I tried burning netherrack as well and the fire went out. I am an op and dont have world guard, the plugins i have are: BetterShop, Cannons, CommandBin,Courier, CreativeGates, EternalWolf, Factions, godPowers, iConomy, mcMMO, MCSpirit, Minequery, MoArrows, MobDisguise, MobRider, NoLagg, PorteCoulissante and WorldEdit. I know its a long list but they all are great plugins, any help?