all new php code now sends the header already sent warning

I have had none of these 'headers already sent....' problems creating php forms in the past with dreamweaver cs3 (on leopard). Now, every single php form generated using dreamweaver returns this warning - without fail. I copied the EXACT code from a working login form into a new page.....the new page, using the same include file is now returning the warning: I am pasting the code that works, and below that, the code that does not work. Even Developer Toolkit, on the rare occasion it doesn't cause DW to crash, seems to be inserting code that does not work properly - same goes for the insert > data objects.

I've attached the code from both pages - page that works at the top, page that doesn't work at the bottom: