Hi,
Actually we have lowered the version number to avoid confusion.
The latest version of ZoomEffect is actually v3.1, which is compatible with Virtuemart 3.x + Joomla 3.x
Since you are seeing v4.0 in your joomla backend, you are probably using the old version. So, please re-install the zoomEffect plugin, you should see v3.1 instead.
regards.