You did not mention if youxxx8217;re on a BES but there is an IT policy to prevent access to the media card.
Another possibility is below from RIM.
Files stored on a BlackBerry smartphone's media card have a .rem extension added to the original file name.
If you attempt to access the file using a computer it returns an error similar to the following:
Unable to display file filename.<x>.rem
If someone helps, tell them by clicking the Thanks button.!! î
Z10 on BES