Issue with world.DrawDebugData()

[ghost]

Initialized world:

var world = new Box2D.b2World(gravity, doSleep);

Created sample ground body:

var groundFixtureDef = new Box2D.b2FixtureDef();
var groundBodyDef = new Box2D.b2BodyDef();
var groundShape = new Box2D.b2PolygonShape();

groundShape.SetAsBox(CANVAS_WIDTH/2,2);

groundFixtureDef.set_density(0.5);
groundFixtureDef.set_friction(0.4);
groundFixtureDef.set_restitution(0.2);
groundFixtureDef.set_shape(groundShape);

groundBodyDef.set_type(Box2D.b2_staticBody);
groundBodyDef.set_position(CANVAS_WIDTH/2, 0);

world.CreateBody(groundBodyDef).CreateFixture(groundFixtureDef);

Initialized and set debug draw:

var shapeBit = 0x0001;
var debugDraw = new Box2D.JSDraw();
debugDraw.SetFlags(shapeBit);

//initialized all debug draw functions; not including here since the code is too long (DrawSegment, etc.)
//also created draw() function from html5canvas example

world.SetDebugDraw(debugDraw);

Everything else seems to work, but when calling world.DrawDebugData(), there is always an error:

Uncaught TypeError: Cannot read property '19952' of undefined

Has anyone encountered this before? Or is there something I missed in initialization? I just followed some of the code from the html5canvas example. Sorry, I'm not very familiar with this but I have been tracing the issue for days since the Box2D files are minified.