Try disabling Sonic Studio for the duration of your VoiceAttack session and see if that helps, as it has caused issue with some users.
Also, can you do me a HUGE HUGE HUGE favor? In your Task Manager, can you tell me how Sonic Studio is listed? If it has an expander arrow out to the left, can you tell me what it is listed as in both the non-expanded as well as expanded? If you don't want reply here, could you send me an email at support@voiceattack.com? The reason is that I'm building a list of software that potentially interferes with VA, so that the user can be warned on VA startup (I don't have Sonic Studio).