No,this is just a warning of haxe 3.4-compiler,this is not an error and you can to ignore this message.
(also line 56 is not involved in the process of compiling and ignored for haxe 3.4+, it needed for older versions of haxe)
But your troubles in old versions of haxe-libraries: stablexui and systools.
This is stacktrace of your last exception:
Called from systools/Dialogs.hx line 36
Called from systools/Loader.hx line 18
Called from systools/Loader.hx line 30
Called from C:\HaxeToolkit\haxe\std/neko/Lib.hx line 35
Uncaught exception - load.c(237) : Failed to load library : systools.ndll
Tomorrow I’ll recheck SUID under Windows