- Edited
@[deleted]: This is a common php error and results often from the try to send headerdata after the body was already generated. The header can be modified by cookies or sessions, too. If you like to call our theme from a external directory you must ensure that headerdata are send before the body is generated. Ensure that external files, functions and code is not included twice and all links are updated correctly. There are a lot of other reasons, why this error can occur. You php error log can give you further hints...