Hello World - package name error

Trying to get the first Hello World example working on Windows. I have this error in VS Code:

Error: Could not process argument Main
Package name must start with a lowercase letter.

My compile.hxml file:
-cp src
-lib heaps
-js hello.js
-main Main
-debug

Haxe - 4.1.4
haxelib - 4.0.2
hashlink - 1.11.0

I guess you have an Haxe file where you defined a package with a name starting with an uppercase letter such as this example:

package Main;

Lowercase the name and this should solve your problem.