HTML scripts suddenly showing up as faulty

I have just updated content on my homepage, but had not changed anything on the two html codes that embed a Google map and a Twitter Widged (apart from moving them further down).
I had saved and previewed, but not published the changes yet. When I preview, I suddenly get a whole list of error messages and neither the widget nor the map is working. I have tried to embed the map again, but still get an error message up about it (and the other ones). It all seems to work fine in the published version. Help, please!