I doubt if the fact that the plane is a tail dragger has anything to do with it .
If no other airplanes have this problem there may be a problem with the flight dynamics of that airplane.
But if all the planes have the same problem check your altitude of your airport it may be incorrect for the area it is at.
Example if your area is say 50 feet above sea level and your airports altitude is say 45 feet above sea level than the air port is below the level of the surrounding scenery this could cause problems. The same holds true if it is to high as well. 8)