Hi,
If that is when you ground the junction of the two series 10k resistors then both upper and lower sections looks good. You should look now at the output of the buffers to make sure the buffers are working right. If the buffers dont work right, the whole thing wont work right either.
With both buffers putting out the right voltages (+0.1v or -0.1v) then the output should look right too, but to see 1v on the output you have to have a 'differential' input of 1v, not 1v on both channels. The simplest is when the lower channel has 1v and upper has 0v, and when the upper has 1v and the lower has 0v. With these connections (and 10k series resistors still grounded) you should see plus or minus 1 volt on the output. If you dont, then the output differential amplifier is not working.
If the output amp is not working then you have to fix that next.
So try that next, keep the two 10k series resistors junction grounded, apply 1v to the lower section, 0v to the upper section, then measure the outputs for BOTH channels at the output of the buffers again, then measure the output of the final amplifier.