Main.hx errors

I got 2 errors trying to compile a game that uses Haxeflixel.
source/Main.hx:3: characters 8-23 : Type not found : webm.WebmPlayer
source/Main.hx:20: characters 36-44 : Accessing this field requires a system platform (php,neko,cpp,etc.)

Normally I would know how to fix error 2, but it’s not the way I thought it would be.
The line the 2nd error mentions is:
public static var preload:Bool = !Sys.args().contains("-nopreload");

If anybody is familiar with these two errors, I’d appreciate the help.

For the first error you might be missing the library in your Project.xml, something like <haxelib name="openfl-webm" /> maybe.
Though it seems to be only available for the cpp target.

The second error likely can’t be fixed, I assume you are building for html5, which doesn’t have launch arguments. So you’ll have to decide which value you will use, I guess it should be replaced with public static var preload:Bool = true;, as it seems to be the default value.