Another user very crashy dullahan_host.exe here, did a full "clean install" including deleting associated appdata folders.
Video stream is a youtube playlist, works in Official SL Viewer, but gives me just a gray screen with audio in Firestorm (both 32 and 64.bit).
Fixed - Problem related to "Max Texture Quality Level' not set to '0'
System info: https://pastebin.com/6cZGUxu7
And I see that this "forum" hole now has ignore. Very useful for people who haz a sad/angreh when asked to use punctuation.