The Dock Shuffle was clearly designed exclusively for the iPod HiFi and other similar boombox and speaker setups.
The standard 30-pin dock connector found on the iPod docking cable does not fit in the Griffin Dock Shuffle.
A Dremel drill is the best tool to increase the size of opening. Although a sharp knife can also substitute.
The opening needs to be opened about one-eighth of an inch along the bottom and left and right sides to accomodate the iPod cable end.
Expanding the opening allows the iPod docking cable to fit.