xna 4.0 - XNA 4.0 contentloadexception was unhandled -

this first time doing xna project.

i've been following tutorial (http://rbwhitaker.wikidot.com/using-3d-models), , i'm having trouble running game, returning error in question.

i've read similar questions here, on net, , have content project, root, custom content manager, etc. now, i'm not familiar of those, modified nothing of xna's template code, added (from tutorial).

and here's code:

    public class mainclass : microsoft.xna.framework.game     {         graphicsdevicemanager graphics;         spritebatch spritebatch;         // below: added of 5/2/13 - referenced tutorial         private model testmodel;         private matrix testworld = matrix.createtranslation(new vector3(0, 0, 0));         private matrix testview = matrix.createlookat(new vector3(0, 0, 10), new vector3(0, 0, 0), vector3.unity);         private matrix testprojection = matrix.createperspectivefieldofview(mathhelper.toradians(45), 800f / 480f, 0.1f, 100f);         // code ends here          public mainclass()         {             graphics = new graphicsdevicemanager(this);             content.rootdirectory = "content";         }          protected override void initialize()         {             // todo: add initialization logic here             base.initialize();         }          protected override void loadcontent()         {             // create new spritebatch, can used draw textures.             spritebatch = new spritebatch(graphicsdevice);             testmodel = content.load<model>("models/g01-12-13.fbx");         }          protected override void unloadcontent()         {             // todo: unload non contentmanager content here         }          protected override void update(gametime gametime)         {             // allows game exit             if (gamepad.getstate(playerindex.one).buttons.back == buttonstate.pressed)                 this.exit();              // todo: add update logic here             base.update(gametime);         }          protected override void draw(gametime gametime)         {             graphicsdevice.clear(color.cornflowerblue);              // todo: add drawing code here              base.draw(gametime);                     }     } 

it errors on testmodel content load part. says can't find model. i've tried putting outside folder, no avail. can have on this? thanks.

p.s. i'm using xna 4.0, visual studio 2010, , windows 8 (ugh).