Layout + Sessions headers already sent by

[eluser]Jelle Victoor[/eluser]
Hey,

I'm using the Layout library. But when i use sessions together with this I get the error, headers already send by.
I can't seem to locate the problem because I don't see where the session lib is sending out headers.
Also, when I do a redirect I get this problem, I understand that redirecting is sending headers, but I don't know how to let a lib work together with the session lib and getting no errors for the headers.

Thank you

Jelle