re: Dow futures down 100, eastern indices open down.

Yep. That appears to be the main catalyst for the > 1% drop in European markets today.

Other things happening in the background:
* Deutsche Bank issues hiring freeze, and other European banks aren't looking very healthy either
* Sturgeon indicates that Scotland may have another independence referendum, as the future looks bad for UK-EU trade negotiations
* the GBP dropped again earlier this week, but has stabilized for the past day or two, and import inflation is only expected to hit hard after Christmas
* the FOMC meeting minutes from September showed a quite hawkish contingent in a 7-3 vote, and so it's likely that the Fed will begin tightening on November 2