Same thing happened to me! :swear: !!! It seems Steam hates modders.
Steam svcks... Period.
HA! VALVe (the owners of Steam) actually worked with the creators of either OBSE or FOSE to get it working with Steam. They've taken popular mods and advertised them, given them publicity, and still let users download them for free. They've added popular mods to their games and allowed users to donate to the creators who are now $10,000s richer.
Steam LOVES modders. NVSE just need to update.
EDIT: Woah. Few hours late there. May or may not have been ninja'd several times. May or may not be beating a dead horse. Oh well.