Most likely they were not pornographic files did they all happen to be 8651.7kb in size. There is a virus that will remake itself 1000's of times running around on the Gnutella net. It is most likely that she opened one of these files and it started duplicating itself. You will find this virus in almost any software search you do on the gnutella net. This file renames itself then duplicates.
The link below should be of some help. Also this virus disables most anti virus software.
http://www.gnutellaforums.com/showthread.php?t=41432