After deactivating those 5 additional plugins and restart the SQ 5.6.6 instance, the binding works.
Must be one of these plugins:
sonar-android-plugin-1.1.jar
sonar-rpg-plugin-2.1.0.736.jar
sonar-tsql-plugin-1.0.1.2094.jar
sonar-vbnet-plugin-4.0.0.115.jar
sonar-vb-plugin-2.2.1.886.jar