question to sessions

[eluser]RcCluster[/eluser]
hi,

i do a query and try to store the result in a session-var

Code:

if ($Query->num_rows() > 0) {
  $rows = $Query->result_array();
  $this->session->set_userdata('ausgabeArray', $rows);

but i get no output then.

if i change the code to

Code:

if ($Query->num_rows() > 0) {
  $rows = $Query->result_array();
  echo "mist";
  $this->session->set_userdata('ausgabeArray', $rows);

then there is the right output except the errors at the top of the page (Message: Cannot modify header information ...)

is there someone out there knowing things like this?

thanks
RcCluster