Well, it's all a bit circular... that's the error code (and message) for not being able to find a message.

The code is a constant, so for example if you try and print error messages 2020-2030 using:
Code:
For $i = 2020 to 2030
	$=Execute("Exit "+$i)
	@ERROR " " @SERROR ?
Next


You will get the "message does not exist" error for codes 2023-2030 because they don't have a valid message:
Quote:

2020 The specified color transform is invalid.
2021 The specified transform does not match the bitmap's color space.
2022 The specified named color index is not present in the profile.
2023 Error (317 / 13D) while retrieving error information for 7E7
2024 Error (317 / 13D) while retrieving error information for 7E8
2025 Error (317 / 13D) while retrieving error information for 7E9
2026 Error (317 / 13D) while retrieving error information for 7EA
2027 Error (317 / 13D) while retrieving error information for 7EB
2028 Error (317 / 13D) while retrieving error information for 7EC
2029 Error (317 / 13D) while retrieving error information for 7ED
2030 Error (317 / 13D) while retrieving error information for 7EE



BTW the error message text is a Windows API feature, not a KiXtart feature.