import { Component } from '@angular/core';

@Component({
    selector: 'my-app',
    templateUrl: "tpl/app.component.tpl.html"
})
export class AppComponent { }

import { Component } from '@angular/core';

@Component({
    selector: 'my-app',
    templateUrl: "/app/app.component.tpl.html"
})
export class AppComponent { }

Use full path of templateUrl
Use full path of templateUrl
