Headersession and other local and server problems

Headersession and other local and server problems I use window7, using PHP5 + MYSQl + Apache for development, how can I use it locally, but uploading it to the service won't work, and the header won't work either, the session does not work either. Urgent. if sessionstart is placed in the most header session and other local and server problems
I use window7 and PHP5 + MYSQl + Apache for development. it can be used locally, but it cannot be uploaded to the service. The header does not work, and the session does not work. Urgent

------ Solution --------------------
If the session start cannot be placed at the beginning, change output_buffering = off in php. ini to output_buffering = 4096.