What do you mean by I'm inserting information to my entity bean?
This looks like this is a Servlet issue. Are you trying to do a server side redirect after you send some data to a client. I belive the message is saying data has already been committed to the response stream so the buffer can not be reset.
you were completely right.. it was a servlet problem..
I was using a variable in 2 different contexts, so my servlet was redirecting to a jsp page but it was also executing other statementes in the servlet..
thanks for your help