I haven't had the trouble unlocking the powers as such, but I am having an issue of a similar nature. After reaching level 30 I have lost the dragon souls I had prior, and now I am finding that I can't absorb souls either so unlocking new powers is now becoming somewhat of an issue. I am not entirely certaina s to whether this is a bug or if I was a little too hasty in my use of the dragon souls I had already aquired, perhaps even unlocking storm call was a mistake so early on, thus far I have killed a total of 3 dragons, 5 blood dragons, 2 frost dragons and 1 named dragon after reaching level 30 and have only been able to absorb the soul from the 2 of the blood dragons, 1 of the frost and the named one. When it first happened I thought it was merley a single glitch and shrugged it off until I unlocked the power he was guarding and I had found that my souls were gone. Don't get me wrong I am loving the game, 4 days straight and still so much left to do but this issue is rather disconcerting.
Where did it first happen? I've had a similar glitch and have to wonder if it happened at the same place. I've played about thirty hours and killed five or six dragons, no soul-svcking problems, but then I was inexplicably unable to absorb the soul of the last beastie I killed. It happened at that small mountain near the boneyard in the hot springs area, at that exterior word-wall where you learn the frost breath. I killed the dragon, same as before, and once the deed was done the critter just flopped there looking stubborn and dead. I tried reloading and killing it several other times, leading it off to other areas more than once, and still the same flaccid end. No fire, no mystical effects, no dragon soul, just a ten-ton sack of dead, insolent meat. I can ignore graphics errors and bandit arrows hitching a permanent ride in my character's head, but an inability to carry on with the central focus of the game? WTF?