OK done a complete re install, installed blocks b and c, re started comp, installed block F, restarted comp and I can now input the weights!! I wonder if there is some coflict between the ACE weights section and the FMC as I did not use the ACE this time and everything worked ok.  Just having the same probs as everyone else now with the auto throttle not disconnecting properly on approach ie you disconnect it to fly a manual appraoch and the speed button on the MCP is still illuminated even with autopilots, FD and A/T disconnected.  Also having the brakes message on all the time in flight but thats all I can see wrong at the mo, need to have a closer look at the systems later

Rich