Piotr,
I am having an hard time replicating your problem (works here). I presume what you say is you hit “Enter” – Render Effects in work area.
Also check your keyframes are what you think they are, in CS5.5 I noticed the first keyframe is sticky and sometimes does not stay the proper value.
Can you write to techsupport at revisionfx dot com for instructions on how to send a movie + project here?
Pierre