Have you double-checked that you followed all setup instructions?
Though, according to the "Installation" section
here, installing the plugin itself should be a matter of running an executable and making sure the "Enable Plugin Support" option on the "General" tab of the VoiceAttack options window is enabled (checked).
Is there a "Starting EliteVA" message in the log on VoiceAttack's main window, after VoiceAttack is started? There should be a number of messages in the log generated by the plugin, if it's working correctly.