The possible causes are:

1. When editing an axis coordinate after the cutting conditions (F, S, T or D) or the "M" functions.
2. When the marks of the block skip (conditional block /1, /2 or /3) are not at the beginning of the block.
3. When programming a block number greater than 99999999 while programming in ISO code.
4. While programming in high-level, the value of the RPT instruction exceeds 9999.

The solution for each cause is:

1. Remember the programming order.2. Remember the programming order.

 Block skip (conditional block /1, /2 or /3).

 Label (N). "G" functions. Axis coordinates. (X, Y, Z…). Machining conditions (F, S, T, D). "M" functions.

1. Correct the syntax of the block. Program the labels between 0 and 99999999.
2. Correct the syntax of the block. Program a number of repetitions between 0 and 9999