Update your settings

Hi.
Currently using Siemens 840D SL on a Hermle C50U
I am relatively new to this system however I have managed to program radius compensation successfully in the past but today this is not the case and I cannot figure out why.
The problem being that the radius compensation is activating (shown on screen as active)
but is not physically moving the tool in the X axis to compensate as programmed. one of the lines in question is N2645
for reference 20mm dia endmill used.
Below is the program.
N2590 ;
N2595 THIRD_STEP:
N2600 STOPRE
N2605 TRANS Z=-R23
N2610 STOPRE
N2615 D1
N2620 G00 G17 G54 G90 Z300
N2625 M25 M27
N2630 A0 C0
N2635 S764 M3
N2640 G01 X0. Y=R70 F1000
N2645 X0 G41
N2650 Z50 F1000
N2655 Z10 F500
N2660 M8 ; COOLANT
N2665 Z0. F=R71
N2670 C=R75 F=R71/R72
N2675 G03 X-17.205 Z2 CR=75
N2680 G01 Z300 F1000
N2685 A0 C0
N2690 X0 G40
N2695 X0. Y=R70
N2700 X0 G42
N2705 Z50 F1000
N2710 Z10 F500
N2715 Z0. F=R71
N2720 Y=R70 F=R71
N2725 C=R74 F=R71/R72
N2730 G02 X17.205 Z2 CR=75
N2735 M9 ; COOLANT
N2740 G00 Z300
N2745 Y300
N2750 X0 G40
N2755 G01 A0 C=-R54 F1000
N2760 STOPRE
N2765 ;
 When trying to troubleshoot I input a "STOPRE" either side of the G41 line I get an error from the control but am unsure if it is relevant
additionally when removing the "X0" I get the second error as listed below but again not sure if relevant as I cannot see an issue with my programming above.
errors below:
"too many empty blocks between two traversing blocks with active tool radius compensation"
"selection of tool radius compensation only possible in linear block"
Any ideas? I am at my witts end on this and am tempted to just datum shift in X by + or - 10mm but this is not the proper way to do things!!
Thanks