The #LastErrorLine$ system variable returns the script line number (as a string) for the error that triggered the OnAction Error procedure.
When a script is replayed with #IgnoreErrors = 1, and if the script fails, the error line is not displayed. You can use #LastErrorLine$ system variable to know the line number in the script where the error occurred.
The returned script line number takes into account the number of lines of included scripts.
#LastErrorLine$ system variable is similar to #LastErrorLine. The first one returns the line number as a string, the second one returns it as an integer.