Content changes don't stick

[-LG-]

I have set up a CMS site and any changes I make from my computer show on the site after a page refresh. I have enabled another user with Admin privileges but when they make changes on their computer, they don't always show up on the site, and some changes I have made also don't when they view it. In fact as far as I can tell, they only see the original content I have made that was there when I first gave them access. It looks as if the changes are made, but are not there when I view them. This is driving me nuts, I suspect some problem maybe with caching, file permissions or even script blocking or something by privacy programs, but can't seem to tie it down.

They don't get any error messages at any point, it just looks like the changes have been completed, but they aren't.

Any suggestions?