Assuming you have correctly downloaded the correct OS. Have you deleted the vendor xml? If not and the OS is not from your carrier, it will not load. You want to use loader.exe to load the Os instead of the desktop manager.
Posted from my CrackBerry at wapforums.crackberry.com
also make sure your blackberry is placed where nothing can move it, also try a brand new usb cable most of these issues are cause by a faulty usb cable, plus make sure you are using a direct connection to the pc and not a hub. That's all i can say now.
ive tried everything. when i try to wipe it with jl_cmder nothing happens. the computer recognizes the device is being plugged in but it wont sync to desktop manager.i tried to reload the software through install wizard but when i do it gets to a certain point after erasing and loading new software it says unable to make connection with device. anyone with a problem like this please help!!!