Big black dots appears in animation (blender 2.63, PC)

http://www.youtube.com/watch?v=GtlMtvd0zkM&feature=youtu.be

I’ve seen smaller black dots appear before but not like this. ’
There is pretty much reflection going on both in the steel-material but mostly in the transparent material at the top… Can this cause the black-dots-phenomena?

/Bappe