OMERO.insight is the Java client for OMERO. It is necessary for importing images into OMERO. Please always check that you are using the correct version that matches the server version. 

Also it is necessary to have Java installed on your Windows computer and to have the EXE4_JAVA_HOME system variable set to the path of your Java Runtime Environment program. Download and install Java from java.com. If you need assistance with this please contact IMC help.