1- add parens. String.toLowerCase()
2- eq is deprecated, use ==
3- omit the Scene name, use frame labels only

Code:
on(release, keyPress"<Enter>"){
	if(levelinput.toLowerCase() == "tutorial"){
		gotoAndStop("tutorialstart");
	}else if(levelinput.toLowerCase() == "level1"){
		gotoAndStop("hsstart");
	}else{
		gotoAndStop("invalidlvl");
	}
}