When I connect Scratch Live and the CDJ-2000/CDJ-900, the deck to be controlled cannot be selected. When I press the LINK button, "PUSH TO CONNECT" appears on the CDJ-2000's display, but after I press the rotary selector, "DECK:1" is not displayed.
Check the HID setting in the CDJ-2000/CDJ-900's Utility menu.
To control Scratch Live, set the HID setting to "ADVANCED".