Problem: After having moved some PHP scripts from one web server to another, they stopped working , or only worked partially. One of the webpages showed all the HTML and the upper part of PHP generated code, but strangely after a certain point the rest of the PHP code had just been ignored.
Solution: I loaded one of the script files in the open source DevPHP editor and chose Format on the menu. The Mac (CR) option was checked. I changed it to Windows (CRLF), uploaded the file again and reran it. Voilla, it worked!
Obviously, some PHP parsers may be more picky than others with how they read line breaks.