Nic, the specifications for those 8 post hoc tests don't make sense to me. What exactly are you looking for: the age effect at each time point? If so, it should be something like:
-gltLabel 1 t0_Age -gltCode 1 'Time : 1*t0 Age :' \
If you just want the effect at each time point with Time being controlled at the average, do this:
-gltLabel 1 t0_Age -gltCode 1 'Time : 1*t0' \
Gang