Try the following actions:

• If you're trying to open a media file on your BlackBerry® smartphone and your smartphone is connected to your computer, disconnect your smartphone from your computer.
• If you encrypted the media files on your media card using an encryption key that your BlackBerry smartphone generated and you're trying to open an encrypted media file on your computer or a device other than the BlackBerry smartphone that you used to encrypt the file, insert the media card into the BlackBerry smartphone that you used to encrypt the file. On the home screen or in a folder, click the Options icon. Click Security > Encryption. In the Media Card section, change the Mode field to Device Password.
• For more information about synchronizing media files, see the Help in the BlackBerry® Desktop Software.