A few months ago, I was working on a PHP project in Aptana Studio. It was version 1.5 or something. Later I installed Aptana 2.0 and created a new project with the same files. Back then it was UTF-8 so I chose UTF-8 for the project's text file encoding. When I make changes in any PHP file using Aptana, it gives the error: Warning: Cannot modify header information - headers already sent... I know it's a problem related to encoding. What can I do?