Looking at the specs, in particular figures 8 and 10 on page 6, the common-mode voltage seems to be limited to 25V for +/-15V supplies.
My question is: where is that 25V measured? At the pins of the IC, or at the inverting and non-inverting input pins of the op-amp? If the former (which seems reasonable, since the specs are given for the IC), then I cannot understand why if I use it in a gain=1/2 configuration, with +/-15V supplies, the circuit would fail with two identical input voltages of 30V (the voltage at the input pins of the op-amp would be 10V, which is within the power supplies range).
Can you confirm? (or clarify if there is something I'm misunderstanding?)