Follow the link I posted above or this one (http://rsbweb.nih.gov/ij/download.html). There is no ImageJ 4.3.3. That's the version number of the OMERO plugin. You must first download and install imagej. And best, read their documentation first, too. ~Josh
We can't provide general support for using imagej. You'll need to contact their users' list for that. If you have a specific, OMERO-related question while using ImageJ, let us know.