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Confused again!!!!

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After info from this site and a little GE internet search I found this. My lights have a S 51 ballast. Each bulb in the 6 lights that work are a GE Multivapor MVR 400/U/ED28R and the bulb package has M 59 ballast on it. Do I assume these bulbs can work in these lights or somebody put the wrong bulbs in all of them? Some of the lights dont work and the bulbs look good.
I resistance checked a few of the lights that dont work ballast taps. Some are multiple voltage fixtures. Each of the resistance checks goes from 1 to around 4 ohms. I assume the difference is the 480, 270, 220 or 120 volt hookups. I was hopeing for an open circuit in one of them. Am I to assume the ballast is good? Maybe the bulb is bad? The starter board? How would I check that? Oh and thanks for all the help so far. And no I am too cheap to put better lighting in. These lights suit my minimul usage just fine plus they were all free!!!