Originally Posted by mouseberry
Correction, it says;
The Blackberry Desktop Software does not have Blackberry Device Software for the device you have connected to the computer. Contact your wireless provider or system administrator.
"Blackberry Device Software" means the OS installed in your BB, mouseberry.
Go to T-Mobile UK's web site, download the file that contains the OS in your BB (may be an upgrade), and install it in your hard drive. The file is huge, ~85MB, so use a higher speed Internet connection.
Desktop Manager uses this OS copy as a reference for advising what is installed in your BB, and to allow updating (if applicable) or deletion of software, video, and other files types.