Angular 2 Typescript @injectable

im using angular2 version 2.0.0-rc.5 and i create a file name userdetails.ts

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

export interface userdetails{
    userid: string,
    password: string,
    name: string,
    sbu: string,
    division: string,
    position:string,
    loggedin:boolean
}

@Injectable()
export class Userdetails implements userdetails {
    public userid: string = null;
    public password: string = null;
    public name: string = null;
    public sbu: string = null;
    public division: string = null;
    public position: string = null;
    public loggedin: boolean = false;

    constructor(){

    }
    isLoggedin(){
        return this.loggedin;
    }
    userSBUdetails(){
        return this.sbu;
    }
    getUserdetails(){
        return {userid: this.userid,
              password: this.password,
              name: this.name,
              sbu: this.sbu,
              division: this.division,
              position: this.position,
              loggedin: this.loggedin};
    }
    resetDetails(){
        this.userid = null; 
        this.password = null;
        this.name = null; 
        this.sbu = null;
        this.division = null; 
        this.position = null;
        this.loggedin = false; 
    }
    setDetails(data){
        this.userid = data.userid; 
        this.password = null;
        this.sbu = data.sbu; 
        this.division = data.division;
        this.position = data.position;
        this.loggedin = true; 
    }

}

and the next step i import it to the app.module.ts

import { NgModule }       from '@angular/core';
import { BrowserModule }  from '@angular/platform-browser';
import { FormsModule }    from '@angular/forms';
import { HttpModule }     from '@angular/http';
import { AppComponent }       from './app.component';
import { routing,
         appRoutingProviders } from './app.routing';
         //all child route
import { DominoMenuRouting } from './domino.menu/domino.menu.routing';
import { MAPMenuRouting } from './map.menu/map.routing';
         //all component
         //domino.menu
import { DominoMenuComponent }  from './domino.menu/domino.menu';
import { PizzaComponent }  from './domino.menu/pizza/pizza';
import { ToppingComponent }  from './domino.menu/topping/topping';
         //map.menu
import { MAPMenuComponent }  from './map.menu/map';
import { AdminUserComponent }  from './map.menu/admin.user/admin.user';
import { DomUserComponent }  from './map.menu/domino.user/domino.user';

import { LoginComponent }    from './login/login';
import { MainMenuComponent }    from './main.menu/main.menu';
import { Httpprovider } from './httpprovider';
import { Userdetails } from './userdetails/userdetails';  <<--

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    routing,
    HttpModule,
    DominoMenuRouting,
    MAPMenuRouting,
    Userdetails  <<--
  ],
  declarations: [
    AppComponent,
    LoginComponent,
    MainMenuComponent,
    DominoMenuComponent,
    PizzaComponent,
    ToppingComponent,
    AdminUserComponent,
    DomUserComponent,
    MAPMenuComponent
  ],
  providers: [
    appRoutingProviders,
    Httpprovider
  ],
  bootstrap: [ AppComponent ]
})
export class AppModule {
}

but when im ruing it, i got an error say that

VM60:18 Error: TypeError: Caot read property 'type' of null(…)

but if i remove the userdetails from app.module.ts the application working fine, its there something wrong with null statement?