try the method in the root progress thread firstly before asking questions, your venue 8 might be one of the ones that isnt patched yet also download the bluebox app from playstore as that app will most certainly confirm or deny if your tabby can be rooted.
I used the impacter method on mine(straight out of the box-didn't take any updates) and then blocked it from getting updates until we get something for 4.3.
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