Delay btwn my screen and participant

Delay btwn my screen and participant

I gave things a test run today - set up a meeting w/a friend
I was a presenter, using windows OS, firefox browser - she uses Mac/Safari
We got the meeting set up no problem - nice and easy!
But then we discovered that there was a very long delay btwn when I'd do something on my screen vs when she'd see it - took btwn 30-45 seconds for her to see what I'd done
The first time she used the Flash option for viewing.  Tried again using the java option. both were equally slow.
Any thoughts/suggestions?