I've just double checked and it's definately not our end that is doing it, the replay link uses %20 for spaces which is the html valid code for a space. What email client are you using?
<html><body><center><img src="http://www.raceauthority.com/email_img/ctra_replaysvc.gif" alt="CTRA Replay Service"></center><br><br>Dear Philippe Martin<br><br>Below is a link to download the replay that you requested.<br><br><a href="http://www.raceauthority.com/replayarchive/Single2 SO5R 18 Aug 2007 1512.mpr">Click Here To Download Replay [<small>Single2 SO5R 18 Aug 2007 1512</small>]</a><br><br>The CTRA X-System Admin Team</body></html>