Issues switching between code and design in Dreamweaver

I recently created my first web page in Dreamweaver. I did the page (it's just a splash page at this point) in .css and everything was working fine. I opened the site in Dreamweaver numerous times to make edits and upload said edits last week.

Now, suddenly, when I try to open the index.php file, it locks up Dreamweaver. I seem to be able to open the page in code view, but if I try to go to design or split view, I get the beachball and Dreamweaver is basically frozen. My in-house web design guru (I'm a print guy) helped me build the page, and when he tries to open the page, he gets the same issue.

Once in awhile it'll eventually switch over to design view, but in general, it's frozen. and I force-quit DW.

This is ONE simple page, so I don't see how I'm having these issues. Other, more complex sites we've built in-house open just fine.... Help!

FYI:
The page is located at www.gaps-seed.com.
Built in Dreamweaver CS3 on an iMac 2.4 C2D.

 

update: so DW finally loaded and I was able to make the edits I needed, but I'm still having the issue when I try to open the page... lag lag lag...

Any suggestions would be hot.