Yes Peter, you had a UTC timing error. But you made me go and check Jupiter 2. At home I didn't have Jupiter 2 installed, so I used Sky View Cafe (
http://www.skyviewcafe.com/index.php ) when I replied last night. Yes, Jupiter 2 also shows the 6:46pm transit as Europa. Of course, Europa's shadow transits at a different latitude on the planet - you might have been concentrating elsewhere?
One thing is to get the orientation (N/S, E/W) of the software display the same as you see through your eyepiece. I use the positions of the Moons to clarify that - look for a time when you have a clearly unique distribution, both E/W (say three on one side and one on the other) and N/S (Ganymede is useful for this - it moves clearly from N to S as it orbits).
I think you should also put your moon filter on, to reduce the light. That's probably the green filter?
Everyone else, am I missing any suggestions for Peter to help him see these shadows?