juliaeb 0 Newbie Poster

I have a confusing anomoly and so far no tech I've asked can figure this out:
In my business I run a website that I develop from my computer which networks to the server (so the actual root web sits on the server) then I upload to the web host. (I use Dreamweaver)
I use a lot of php. However, when I preview the PHP frameset files it breaks them apart and shows each frame in a separate window instead of as a whole frameset. Once uploaded it works fine.

The anomoly is:
I also do a lot of development on my home computer and when I preview these PHP frameset files on my home computer (where I am not networked to the server but instead just copy down the files, work on them then upload) the framesets preview correctly - all in the same window.

So, it makes it really hard to do PHP development from the business and I have to do most of it from home.
Any ideas as to why the PHP framesets preview ok on the standalone but not on the networked computer? HTML previews fine no matter which computer I use.
thanks
Julia