FFmpeg filter_complex says filter not connected to source
You can consume a filter generated stream only once, unlike streams from -i inputs. Since [vid] is already supplied to the first trim 60:65, it can't be reused. You can add a split and supply a copy to each:

nullsrc,split=2[vid1][vid2]; ... [vid1]trim=60:65, ... [vid2]trim=120:125, ...