if it's only in /usr/share/hildon-welcome/media/ you can remove it via mc (i don't use it... so i'm only guessing) or
1. open xterm
2. sudo gainroot
3. rm -r /usr/share/hildon-welcome/media/~media
if it's still in /opt/media/ then you did something wrong with my commands above ^^
and if the ~media folder shows up anywhere else... you did something really strange wrong o.O
and in this folder your movie-files show up, right?
if yes then i would say... you're ready to go if you followed my other instructions with chmod 777 /usr/bin/rvid and chmod 777 /etc/event.d/rvide after moving the files to those places ^^
(and of course having the default.conf and x.conf files in the right place)
just reboot your phone and report what's happening
and in this folder your movie-files show up, right?
if yes then i would say... you're ready to go if you followed my other instructions with chmod 777 /usr/bin/rvid and chmod 777 /etc/event.d/rvide after moving the files to those places ^^
(and of course having the default.conf and x.conf files in the right place)
just reboot your phone and report what's happening