[ddouglass]

The additional items that were being included in version 4.0 will be in free upgrades as those items are worked out. Getting the basic package working correctly has been costly and very time consuming for MTU. And as Beavis said the biggest problems have been Microsoft and Vista which is plaguing all software producers and Microsoft keeps trying to shove down our throats.
Because they (MTU) knew that a lot of problems were going to show up they included a copy of version 3.321 updated to work under the 4.0 registration code. It is a file in the Program Files\...\Hoster folder and named Hoster34.exe. That way you can go ahead and upgrade and if it doesn't work right switch to using the 3.4 version and use it until they release the next update.