The page cannot be displayed

I have created a website with DreamweaverMX which has an Index.htm file containing frames. When I open a version of the file from July 2005 it opens just fine and I can see the htm files displayed in the frames. When I open a version of the file saved 4/4/2006, with no changes, just resaved, every frame shows “The page cannot be displayed”. I am using IE6.0.2900 w/128 bit encr. on a WinXP SP2 machine. The web files are just located in a file on my hard drive and not hosted with IIS. The individual htm files that go into the frames all display just fine by them selves. Some of the files have behaviors coded in for some of the links. Can anyone shed some light on this issue? Help!!!