One thing to remember is that these wide doors are heavy and require several components to work in tandem to ensure proper and smooth operation. In general when the opener begins to pull the door up it puts a tremendous amount of force on the top center panel. Usually there is a metal band which runs across the top panel. This band sits on risers which act as a brace and counter force against the pull of the opener. I often see this band out of position and loose. Make sure it is tight. Also check the cables for tightness. Check also to see if the door is freezing along the bottom seal. If everything looks fine I recommend calling a local overhead door company.