Hi Mark, thanks for the help!
One of the first things I tried was to install that codec but it refuses to install because “A newer version of this codec is all ready installed!” message is shown and then the installation is aborted.
I guess that this new version comes with Premiere CS4 because I can open that file only with it, quicktime player and other editing and compositing softwares where unable to open the files on my windows rig.
Maybe those files are somehow specific too, depending on the camera model that filmed them?
Best Regards,
Niki