Well,
the rx problem means that the 4000 forwards (floods) packets to the other swicth, this seems to be normal.
Otherwise, the point is to know what makes these errors; it very likely can be a LAN card trasnmitting bad formatted packets, or a cable issue getting the same result. If you cannot find out trhough toptool or other tool which one does it, I would, if I were you, try to unplug one by one each cable coming to the 4000, wait a bit to see if the problem stops : then you get the wrong cable, test it. If it works, then it's the NIC of the machine connected.
Check also that you do not have 2 connections between 2512 and 4000, and taht the connecting cable is properly set (straight or crossover, plugged on uplink or not).
Last, your English is far good enough to be perfectly understood, far as good as mine anyway.
J