Could Not Find or Load the Qt Platform Plugin “xcb”

If you get the following message when trying to run “atkpython” on certain Linux platforms

 This application failed to start because it could not find or load the Qt platform plugin "xcb".

then you need to install the xcb library. On Debian-based systems (such as Ubuntu) this is in the “libx11-xcb1” package. This error may also prevent you from starting VNL. In this case, esp. if you double-clicked the Desktop icon, no error message is shown, but the text above can be found in the crashlog.txt file, which will be created in your home directory.