Check out this thread ... :
http://www.gnutellaforums.com/showth...&postid=174675 but it is possible that you have a faulty file, in which case nothing you do will get it to open in iTunes. ...although it might open in another application.
Also it is helpful to use Bitzi look up to check files before downloading ... see:-
http://www.gnutellaforums.com/showthread.php?t=37676
btw Please do not name copyright titles on the forums as it against the forum rules .... also please try to post in the correct forum for future threads. Beta is only for testers of the latest officially unreleased versions.
I hope some of this helps