Droid X Mp4 problems

[Texas510]

Hello forum,

I have had my droid x for 6months now and finally got around to downloading movies onto it. today i downloaded a copy right protection free version of star wars episode 3 onto my phone. it was in mp4 format (854 x480 video), aac audio, etc... (converted using freemake's android feature). yet on my droid it was unable to play in the gallery. Is there anything I should look at or change in the settings? all suggestions/comments are welcome

 

[DroidXDoes4G]

Sometimes certain files don't work.
I have downloaded and watched probably 100+ movies,
and about 10 of them just didn't play.

(most of the older ones tend to not work)