I'm running DW CS4, but this seems to be an issue with Dreamweaver in general.
On trying to make a simple change to a page, I couldn't open any of my pages and kept getting the message "Dreamweaver Not Responding". I emptied my cache - I restarted my computer, I tried other sites - to no avail. But I found I could create a new page without any problem, so it was my code.
On searching the forum I found a fix (Thanks Cool Dawg) - Turn off "Display External Files" (found under "View"). I now had access to my pages. (If you have an old Dreamweaver installation you won't find this option, but read on).
I then searched for "WHY?" And it looks as if it's my Facebook Badge causing the issue. By turning "Display External Files" back on and then commenting out the FB code, everything worked again. So, before you delete cache and other files, try commenting out different portions of external code to find the culprit.
I still want to know why this is suddenly an issue, everything was working fine 10 days ago.
I hope this will help anyone who lands here to save a bit of time.
Ahem ... that's "codeDawg" (but thanks for the 'Cool' compliment )
Here's a link to the original thread with the solution and some guesses as to "why" this is happening.
There's also a post in there for folks running Dreamweeaver version 8, who may not have the "Display External Files" option available.
My guess is that Facebook made a recent change to the FB badge jscript.
A change, either in the jscript itself or the html generated by the jscript, that DW-design-view has a hard time rendering.
I've also been having this problem with Dreamweaver 8 on an XP Pro system.
I solved it by designing my own artwork, and using that to link to the relevant Facebook page instead of having an official Facebook Badge. Can't see any reason why that shouldn't work as well for me.
I had no problem with the original badge for some months, so it's a change to their script that has caused the problem. Seems fairly typical of their attitude to their users - look at what is happening over Timeline.