I think some wheels jsut don't measure up for one reason or other that we can't identify. There is another thread where I talked about a wheel giving me grief from new.

I'd suggest a whole new wheel including hub. Maybe the hub flanges are out of whack. Who knows. I hae just gone to Velocity rims (with the Off Centre rim and Velocity hub and spokes on the rear) and have zero problems in around 6000km. They are 700C rims. I would not expect their 26" rims to be any different in quality.