Door sticks since installing new knob

Question: I installed a door knob on a door, and I had to drill the holes. The knob fits in the door alright; however, when I tighten it to the door, the latch won't work properly - it sticks open when I turn the knob. As soon as I take the knob out of the door, it works fine. What am I doing wrong?

Fourchalk: You drilled the holes at an angle through the door. If you re-drill the holes straight you will find that the door knob will work fine.