T4= Tool 4 you can only call ( 1 ) Tool in your program you have more than one T call so will be a problem
(T2 D=0.125 CR=0.0625 - ZMIN=-0.015 - ball end mill ) Use parentheses
(T4 D=0.1875 CR=0 - ZMIN=-0.35 - flat end mill )
(T5 D=0.25 CR=0.125 - ZMIN=-0.0491 - ball end mill )
N0 G90
N1 G17
N2 G70 ( Remove the G70 )
N3 G53 G0 Z0 ( Remove the G53 )
; Ramp1 ( remove the Ramp )
N4 T4 M6
N5 T5 ( Remove the T5 )
N6 S5000 M3
N7 G54
N9 G0 X0.1255 Y0.7255