Good morning Les.
Was wondering if you have ever come accros this before.
Late last week I went to cut some material. Did all the post processing in sheetcam, did a simulation and all was OK. When I ran the G code in Mach3 it came up with 'error Riik words all missing from arc. Block=NO420 Z57.150.
It has something to do with my Z axis, however I do not know what that is.
Earier that week I did an update of sheetcam as the notification came over the web. I have never encountered this before. Do you have any suggestions. 
What post processor are you using? Most of the Mach posts should have code to make sure the ‘RIJK codes missing’ error does not happen.
Good morning Les.
The post processor that I am using is
Candcnc DTHC-HYT-TAP_Softpearce+Marker-rev 11D.
I have been using this post processor for some time and no problems.
Could the update to the latest version of sheetcam contributed to this 
I don’t have a copy of that post. I have a couple of similar posts but they look correct. Could you send me a copy of your post.
I sent you a modified version of that post. Let me know if it works.
Thankyou Les will do so and report back
I suppose you have a G2 or G3 in one of the lines before the line creating the error message.
G2 / G3 is modal and stays in effect until it is changed.
Add a G00 or G01 in front of the Z move and see what happens.
Richard