Did you use the list from MTU to make the changes?
http://www.mtu.com/upgrades/hoster/v...de-hoster4.htm
He may have something running in the background that is causing this, like an Anti-virus program or a service that isn't needed.
There is one other fix that isn't listed there that you can try.
Determine the amount of time the lag is. Close Hoster 4.06 and open Hoster 3.4 (file is located in C:\Program Files\Micro Technology Unlimited\Hoster and named Hoster.34.exe).
Go to Tools\Playback Offset and change it using the + side since audio is lagging video. Close 3.4 and reopen 4.06 to test it.
This control has been added back into the next release.