A while back I wrote a tutoria called Aerial HDR workflow process this tutorial uses the old possibility in Photoshop to open a 32 bit HDR file directly in Adobe Camera raw.
In the latest Photoshop CC Adobe has disabled the posibility to open 32 bit HDR directly in Camera raw. And while your still able to click the button all you end up with is a error message.
To bypass this error you have to settle for a 16 bit HDR image :-(
Go to Image->Mode->16bit Channel a pop up will open asking you if you want to merge click dont Merge and finally choose Camera Raw
You can read more about it on Adobe here