No output is created using the "
Machine Control" -->
"Insert" event (please see image below)

Solution
The post processor needs to be updated by Importing the custom command
"pb_cmd_user_defined_text.tcl"
Select the following while editing the Postbuilder post processor...
- Select "Program & Tool Path" --> "Custom Command" --> "Import".

- Select "pb_cmd_user_defined_text.tcl" and select "Open".

- Select "OK" when prompted with the "New Code" .

- Select "Program" --> "Machine Control" --> "Insert" (please see image below).

- Add "PB_CMD_user_defined_text_command" to the "Insert" Event (please see image below).

- Save the post processor.
Hardware/Software Configuration
Platform: INTL64
OS: windows
OS Version: 1064
Product: NX
Application: CAM
Version: V1899
Function: POSTBUILDER
Ref: 002-8509337