Can you try that with WinSCP 4.2.5?
I am using WinSCP 4.1.9 (Build 416), host OS is Windows XP
I am connected to a Linux Target via SFTP. When the target restarts I get a disconnection message, asking whether to Reconnect. If I choose to reconnect before the target is back on-line, the process fails (which is OK). Now when the target is back on-line I try to refresh the view in order to trigger re-connection, or try to go to parent folder or go to root folder - I got the "Invalid access to memory" message.
What is really bugging is that even when I try to close the session or close the application I get the same message so I'm not able to gracefully close the WinSCP and restart it - has to kill it via Task Manager