Cannot modify header information

[bigkiss]

What exactly causes this error:

<br />
<b>Warning</b>: Cannot modify header information - headers already sent by ...

It's occuring on the server side of a XML-RPC function call. I tried using ob_start(), but then I get no output at all.

Thanks in advance for the help!

[laserlight]

maybe you could give the snippet of code where near the line of the error?

It might be that some xml was written before a header(), but with this little information I dont think we can say much.

[Weedpacket]

This warning is covered in the PHP manual's FAQ. Note also that if you use [man]ob_start/man to start output buffering, you'll need to use one of the other ob_* functions as well (to finish).