You might want to update to the latest WinUAE. Download the latest ZIP archive from www.winuae.net,
unpack it and copy WinUAE.exe to AmiKit\WinUAE folder and replace the old executable there.
OR uninstall and install AmiKit 1.6.0 just to verify the problem is not with your Windows. Download it from here: http://www.amigafuture.de/downloads.php?cat=33
(And don't worry about the Forum website, you're not the first one having the multiple posts so the bug is on my side.. somewhere)
Sorry for the inconvenience.