What does "Voice Command" "Unexpected server error occurred. Please try again." mean?
I was getting this error constantly today, so I went to Settings &rarr; Applications &rarr; All &rarr; Voice Command. From there I clicked Force Stop &rarr; OK then Clear Data &rarr; OK. Then I relaunched the voice command by tapping the microphone button on my Google search widget.

The Voice Command worked perfectly, and I haven't seen the error message in about an hour.