Did you make a jig?
I made one like this:
take a board (I used a piece of laminate flooring) and measure the entire length of the handle (indicate this with dotted lines)
Measure to the center of each connector bolt and mark this on each side and make a dot. Drill this with the appropriate bit.
Measure the center line of the handle. This needs to be centered on each drawer/doorfront.
Then, attach something (I used a piece of Numerar finishing molding) to create a lip for the template to hang it on the top of a drawer or side of a door. This keeps it steady while you drill. Line the inside edge with painters tape to keep it from scratching the surface while you drill.
HTH
ETA: I wish my digital camera wasn't on the fritz...a picture is worth...well, however many words I used here!