Analogous experiments have been reported before where there appears to be superluminal signaling. These results have been explained away as not real examples of faster than light communication:

May 30, 2000
Light Exceeds Its Own Speed Limit, or Does It?
By JAMES GLANZ
http://www10.nytimes.com/library/national/science/053000sci-physics-
light.html
[May require free registration.]

Note though the statement by Cramer that if there were superluminal signaling, this would require signals travelling backward in time is not correct.
Is has been known for several years that the experimental results or relativity could accomodate superluminal speeds as long as there were a preferred frame. Indeed actual confirmation of superluminial signaling could be regarded as experimental confirmation of a preferred frame.

Bob Clark