I used to use LR 1.4 to open raw NEFs all the time (from D70 and D300). I don't know exactly what version you have, but I am thinking that you should be able to update to a newer version of ACR (LRs RAW conversion engine as I'm sure u know) for free if you poke around adobe's website or google around a bit. Heck, I might have even backed up my ACR update and still might have it kicking around somewhere if you couldn't find the download on line. I think in the beginning I had LR 1.3 and I had to do the same, and quite easily (powered by google) I found the free download, instructions and all..... and I think it was on Adobe's website. I can't imagine that the D90 has a different "flavour" of NEFs than the other models I mentioned.