>Problem solved.
>
>The DLL of the SourceGear Vault (3.0 und 3.1) is not totally transferred to .NET 2.0.
>You have to install .NET 1.1 and also .NET 2.0.

My client is 3.5.2.5087 and it requires .net 1.1 only (I think - 2.0 was already installed), but you're right, it won't work without 1.1. There's a newer version out there (4.x maybe?) which is on 2.0, but we stayed with 3.x because for some reason the newer version of the server refused to run.