MACROMEDIA FLASH MX 2004-ACTIONSCRIPT LANGUAGE Reference page 290

throw new Error("Strings to not match.");
}
}
try {
compareStrings("Dog", "dog");
// output: Strings to not match.
} catch (e_err:Error) {
trace(e_err.toString());
}
See also
throw, try..catch..finally
290 Chapter 2: ActionScript Language Reference