blender motion capture question.

Hello, all.
When i have marks tracked and i select 3 of them and click on Set Floor.
Blender said this: Three tracks with bundles are needed to orient the floor.
But i don’t know what i have to do to fix that.
Can someone help me, please?
Ty, already.


This problem could happen when the solve has an average value higher than 3. Clear solving and try tracking another features. Sometimes, when features are too near to the frame´s border the track is lost before it reaches the final frame. Watch this videotutorial about: