Sorry Sport, I said in my first post I was using IE9 when I should have said I was using the online version.
If you guys aren't able to get Casey in the aerobics studio again after leaving the movies, then I guess I made a choice during them that made a difference, or maybe doing the 2 Nicola scenes first did (although the outfit for the second and Sportd's recent comments lead me to believe there's a third Nicola workout, despite getting a "This is the end of my storyline." message after the park). However, I was only able to load the first pic, where Casey is standing in front of a studio packed full of girls, and neither conversation choice offered attempted to load a new image/conversation option when clicked.
I thought that you made a minor change or 2 to the receptionist path, but I was unable to get it a second time despite making the same choices on who to peek and not peek. Anyway the action pic for the receptionist didn't load, but the mirror pic did on the second try (I switched back and forth several times). Also managed to get the Casey yoga session played.
FYI, in case they're not supposed to be, you can fail and return to redo the first Nicola workout, the Cassie/Nicky reception area conversation, and both Casey stretching sessions. I expected a failure to advance to the next scene would have ended your access to any of these girls, but if not then disregard.
Oh, on my last playthrough, I did the first Cassie/Nicky bit, then Nicola through the park scene, then all of Casey's. When I went back to try to do the second Nicky scene or see if I can do a second Cassie scene (until I found the dildo), after being invited during the Yoga workout, I got the 'No one is home" message. The playthrough before, I didn't do Nicky/Cassie at all, but did Nicola and Casey. Going to Nicky for the second apartment scene with her worked then. So the yoga scene will open scenes with Cassie and Nicky despite not having done their initial set, and right now the 2nd Nicky scene doesn't look like it will open unless you did not do the first scene. When I finally found the dildo, the second Cassie played, then the second Nicky was available.