So I chose to go vampire and am learning from Harkon. He tells me to change into a vampire lord and I change, then when he tells me to land and I land he is constantly telling me to land (go from hover to on the ground). I do so but he still repeats himself. I run around the entire room hoping to maybe trigger a response, I jump, sprint, fly and land and still nothing. Could use some help, even if it's a console command. Thank you.

Theres a list of the dawnguard quests for both sides here..

http://www.uesp.net/wiki/Skyrim:Dawnguard_Quests

quests stages are listed at the bottom of each

if a bug gets ya stuck ya can advance the quest stage . may help

player.setstage questID stage

You are in the wrong forum. The Dawnguard add-on has its own forum.