| error-directive: | error <text> |
Causes the Inno Setup compiler to issue an error message with the specified text. Unlike pragma error, text in error directive is not parsed, so it is recommended to use this directive instead of pragma when possible to avoid possible syntax errors that may hide real errors your script is trying to report.
#if VER < EncodeVer(5,4,2)
#error A more recent version of Inno Setup is required to compile this script (5.4.2 or newer)
#endif