If restarting your computer works, what's likely happening is that something is preventing VoiceAttack from shutting down completely.
When you try to start another instance of VoiceAttack, that will detect the instance that's still running, and shut itself down.
Given the messages in the fault log, it's quite possible a plugin is causing this. To rule that out, disable plugin support, close VoiceAttack, open Windows Task Manager, on the "Details" tab find "VoiceAttack.exe", right-click it and choose "End task", then try starting, closing, and starting VoiceAttack again, to see if the issue persists.
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 close VoiceAttack as mentioned.