Today a new KB article and hotfix have been released for RDS on Windows Server 2008 R2. In a specific scenario a RemoteApp session could disconnected and additionally, the following error message is raised: "Because of a protocol error this session will be disconnected. Please try connecting to the remote computer again"
Article ID: 2699817 - Last Review: May 9, 2012 - Revision: 1.0
RemoteApp session is disconnected when the RDP encryption level is set to Low and RDP compression is disabled in Windows Server 2008 R2
"...Consider the following scenario:
- You install the Remote Desktop Session Host role service on a computer that is running Windows Server 2008 R2.
- You configure the Remote Desktop Protocol (RDP) encryption level to Low, and then you disable RDP compression.
- You publish a RemoteApp program on the computer.
- You connect to the RemoteApp program from a client computer.
Because of a protocol error this session will be disconnected. Please try connecting to the remote computer again.
This issue occurs because an incomplete window instruction is sent to the client computer..."
Source and download: http://support.microsoft.com/kb/2699817/en-us?sd=rss&spid=14134