VB.NET: File.Copy error: The specified network name is no longer available.

Today I had a strange problem with a VB.NET program I made some time ago. It simply copies some file from a Windows Server 2003 share to a Windows XP client. Suddenly it didn't work any more, giving the following error: System error 64 has occurred. The specified network name is no longer available. This seemed to happen on a large file.

After some searches I found out that this problem is not really in VB.NET, but actually is an error in Windows Server. It can be fixed with a small registry change on the server. Please see http://support.microsoft.com/kb/892100/en-us for details.