thanks for the reply. Seems like the secondary skills icons "drop teleporter and use" and "use teleporter" do not always work. I got away from the lava problem by putting the teleporter in my inventory, then clicking on it there
I had problems using those buttons as well, so I got into the habit of doing all my teleport stone stuff manually. Works out much better as you can place them exactly where you want them and use them as shortcuts to pass long stretches of looping terrain if you throw them across lava flows and such.
Good luck with the rest of the game.