I am runnign XFCE4.8 in Arch with all updated packages at the time of reporting this bug.
I recently installed xscreensaver.
In Parole, I have the option to "Disable screen saver while playing movies" checked.
This is confirmed by checking: /home/siam/.config/xfce4/parole/parole-media-player.rc which includes the line: reset-saver=TRUE
However, when playing a video file in parole, xscreensaver is still starting after the "Blank Affter" time in Settings > Screensaver.
I can confirm this on Xubuntu 11.10.
I am experiencing this on xubuntu 12.04. Also, this bug seems to be a duplicate of bug 7404.
*** Bug 8440 has been marked as a duplicate of this bug. ***
*** This bug has been marked as a duplicate of bug 7407 ***