Try this:
There is a conflicting drive mapping in Microsoft Windows between the media card and another resource.
Resolution
Note: To complete this resolution, the BlackBerry smartphone user must have administrator rights on the computer.
1. Open the Computer Management console on the computer by navigating to Start > Control Panel > Administrative Tools > Computer Management.
2. If another resource is mapped to the same drive letter as the media card (such as a network drive), change the drive mapping for the removable media. To perform this, complete the following steps:
1. Right-click on the removable media item and select Change Drive Letter and Paths.
2. Select the current drive letter, and change it to an unused letter.