Hmm, I'll have to look it up (or perhaps someone can chime in) but some guesses are:
-that particular one is unsupported - very unlikely
-you do not have the latest update - what build #s are you usinh?
-some glitch or fault?

Not sure if it's worth trying a read from V7? Pretty much everything works better in V8, especially the new stuff.

Is everything connected and powered up ok?