SIte not working in different browsers

I made some minor changes to my wordpress site today ( http://www.altnyc.org ) – I am using the Builder theme, and on the home page, there are three widget areas that should have content:

– the left column is all text (HTML)
– the center is rotating images
– the third column is a twitter widget

The site looks fine on my computer, using Safari (all three widget areas are showing up with the correct content), but when I open the site in firefox on my computer, or try to open it on another computer, the only thing showing up on the home page is the left text column. I’ve tried to clear the cache on the other computers, thinking it might be pulling up an older version somehow, and tried to load it on my iPad. Same thing – missing content.

I am not a programmer, and am a bit of a novice, so I am completely at a loss as to how this happened. It was working fine this morning, but when I made a minor change to the photos in the center column, something clearly has happened.

I’d be grateful for any guidance!