First try went OK. Then I tried one with trees but that went wrong. Then I imported a track from someone else (Rallicross Oulu 1.0) and it had the same problem. Could this be a shaders 2.0/3.0 problem ?
It looks like shader problem with rx plugin. My computer is broken for a while and I wanted to do something on other machine (don't know what kind of card is there) - have the similar crazy lines over the screen after export to RBR... and also when working in BTB (demo installed for a while).
In RBR this happens on every track exported (even earlier nd from somebody else) from BTB. On original tracks from tha game there is no such "effect".