I'll add to Ian's post that it's important to have the newest version installed as found at the NXT download page I linked earlier. I was unintentionally trying to download the blockchain with outdated (but still new-ish) version 1.4.5 when I should have had the 1.4.6 executable (that still identifies as 1.4.5 until the block chain is finished :\)
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New Offers
Offer Code BeneU023: I have 20 UNO to sell for 0.156 BTC
Benefactor, if BeneU023 is still available, I have some BTC for you. Please confirm and I'll send promptly. Thanks!