flashdata problem

[eluser]kisin[/eluser]
i have a strange problem -
im using db session and when im using the set_flashdata method i see the data only after i refresh my page twice.

for example, i use flashdata in my login form when the login falied but the flashdata is only seen on the screen in the second time the login falied.

any ideas what the problem can be or from where to start looking?