Apache, svn, dav, mp42 corruption

[Da Rock]

Just trying to work with a couple of video files on my webdav system 
that aren't working properly for some unknown reason.

I have an apache24 server with a working webdav/svn setup. Most other 
video files are working, but I have a few which are simply not working. 
All is over https (<big grin>).

If I download the file it works from the local system, but if I read it 
over http mplayer, vlc, ffplay, html5 etc I get a corrupt file.

In the logs I get 500 errors - "unable to deliver content".

As I mentioned, other mp4 files seem to be fine - they even appear to be 
mp42 files as well. So I can't work out what is so different with these 
files that aren't.

I've also tried with mod_h264_streaming on (not that it appears to be 
working as I would have expected).

Any ideas on how to debug this one? I've tried my whole toolbox I think...

TIA