First of all, the screenshot:

Second, the explanation:
As you may see, I chose to download just one file from this torrent. Ktorrent says it's completed and seeding in the torrent list (upper 2 red circles), but in the file list it says 98%. Also, when I try to play this file in VLC, nothing appears and the messages window says that just garbage was found and seeks until EOF. Mplayer doesn't play it either.
The chunks tab doesn't report any chunks waiting to be downloaded. The torrent is seeded.
I used the "check data integrity" function on that torrent. It quickly goes to 33% (probably the 1st file that I didn't want), then counts chunks up to 66% and stops (I undrestand it ignores the 3rd file which I didn't want).
I can send you the torrent file, but it's on a private tracker, so you need an acct there to download.

Edit: the same thing's just happened to another torrent - it's 100% on the list, but the files (2 chosen from 4) are about 98% and unusable...
Is there anything I can do to fix this file/torrent without redownloading it?

I almost forgot: Ktorrent 2.1beta1 on Gentoo.

This is allready fixed in our development version, as a quick fix you can unselect the file and then reselect it again.

That's the kind of help I was looking for. thx.