If you disable plugin support, create a new VoiceAttack profile, and add a command to it that'll have an effect ingame (I.E. presses a key that'll activate an ingame feature with an immediately observable effect), does that exhibit the same issue?
To disable plugin support, click the wrench icon on VoiceAttack's main window, and on the "General" tab of the VoiceAttack options window uncheck the "Enable Plugin Support" option, click "OK", click "OK", then restart VoiceAttack