How can I fix my garage door?

My electric garage door has a mind of its own. Lately it starts down and then goes back up, sometimes 2 or 3 times. Is there an adjustment I can make myself, or where do I start? It is a Phyton Chain Glide, 1/3 HP Model OCG550.
Kara, February 2006
Check the safety electric eye at the bottom of the door.
If the eye detects dirt, bright sun, it will reverse direction
detecting an object in the beam.

garage guy, February 2006