has anyone else had problems with the turn valindor into a vampire, quest? the guy in the catle has given me the same quest twice. looks like I.m gonna have to reload.

Is that the Moth Preist? If so, I didn't...

no it's the quest that http://www.uesp.net/wiki/Skyrim:Vingalmo gives you to turn valindor into a vampire, Vingalmo has given me the same quest a second time and I'm unable to complete it.

Did you read the bug fixs. One of them reads about completing the quest...

Who is the target in the Radint quest?

valindor? not sure if that's the right spelling, it's the guy in riftan

It reads that you can kill him if you don't need him for anything and that will tell you you failed the quest but you will be able to start over...

the turning NPC's radiant quest, it always ends up repeating eventually.

The radiants for dawnguard seem bugged as people have been told to turn their spouse, but the NPC in question that they had to turn was someone completely different than their spouse.

The turning random NPC's is almost bound to repeat it seems, as I've heard this issue many times now.
You can console of course on PC, but your only work around may be to kill the NPC.

Sadly, you may have the issue again later on again.

These quests from Vingalmo are bugged. You will continue to get quests to turn the same 3 NPCs after they are already Vampires.
On PC you can use this console command:

setstage DLC1RV07 100

This will put you at the stage of the quest where you need to go back to Vingalmo for your reward. Another fix is to always keep a save from right before you turn in your last radiant quest for the Vampires and keep loading that save until you get a different quest given to you (they are random). You can also kill the NPC you've already turned to get a 'failed quest', but if you want to keep doing radiant Vampire quests you will eventually run into problems again, and have nobody to kill.