Hi.
Its what is in your Nehrim folder that is important here and what you might have ticked in Nehrim Launcher.
Oblivion meshes,misc,textures,sounds should be in Nehrim folder as well (they are copied over during installation. Sometimes when installing Nehrim and data(.bsa) are copied over,they can become corrupt, which is why I first advised to copy texture.bsa from Oblivion and overwrite the one in Nehrim.
If all else fails, save you savegames somewhere, uninstall completely (meaning ini file as well etc) and reinstall.
Unless someome else has any ideas!!!!