I will make it easy for you.

The problem is how the AU is derived and used by Newton in his
application to planetary heliocentric motion.

http://encarta.msn.com/media_4615477...real_Time.html

After breaking several astronomical principles in order to refer
planetary motion off mean Sun/Earth distances he does everyone a favor
and announces -

"I likewise call attractions and impulses, in the same sense,
accelerative, and motive; and use the words attraction, impulse or
propensity of any sort towards a centre, promiscuously, and
indifferently, one for another; considering those forces not
physically, but mathematically: wherefore, the reader is not to
imagine, that by those words, I anywhere take upon me to define the
kind, or the manner of any action, the causes or the physical reason
thereof, or that I attribute forces, in a true and physical sense, to
certain centres (which are only mathematical points); when at any time
I happen to speak of centres as attracting, or as endued with
attractive powers."

http://members.tripod.com/~gravitee/...tions.htm#time

It is not just a matter of being incorrect ,Newton made misjudgements
based on Flamsteed's false 'proof' of axial rotation based on the
return of a star in 23 hours 56 min 04 sec.

The program tonight on Horizon will be just another useless exercise on
Newtonian adulation regardless of what they think is wrong.He really
was incorrect but there is nobody around good enough to match his
maneuvering.