Moving this discussion to the Camera RAW forum.
The error means exactly what it says: your camera model (Nikon 1 J1) is not supported by any version of the Adobe Camera Raw plug-in that would run on CS5, now or ever.
That camera was first supported in ACR 7.2 (and by higher versions of ACR by now), which needs Photoshop 13.x (also known as Photoshop CS6) or Photoshop 14.x (Photoshop CC).
You will never be able to open those files directly in CS5, as CS5 is not supported any longer and there will never be any further updates for it.
Your choices now are (1) to upgrade to CS6 or to CC, or (2) to look for, download, install and run the free, stand-alone Adobe DNG converter to convert your raw NEF files to raw DNGs that you can then open in your version of ACR in CS5.
Your post was moved to this Adobe Camera Raw user-to-user forum by an Adobe staff member from wherever you posted it first.
I'm a user just like you.