millennial media ad sizes are screwey

my ad sizes are screwy on my android phone - nexus 4.

i am still getting the "test" ads, which is what i want. however, regardless of the size i put, i get an ad that says "728*90" in a green square, and then some text.

the problem is, the whole image from the ad never shows - it is always a portion of an image.

so, while my code reads:

millennialMediaModule.createView({
    apid: "apidhere",
    top: -widthOfScreen*0.01,
    width: 728,
    height: 90,
    adType: millennialMediaModule.TYPE_BANNER,
    ignoreDensityScaling : false,
});

the ad doesn't appear to fit the square - it is way too big.

changing the ad sizes - using dp, or a different set of values - doesn't help either, the ad itself is too wide for my nexus 4 screen width!

can someone share the size dimensions for how they got their ads to appear please?