Snowdrop installer doesn't install Snowdrop add-on for EAP 6.2.0.ER6 properly. It is due to snowdrop-module-installer/pom.xml. The namespaceContexts are specified there, the namespaceContext <s> has value 'urn:jboss:domain:1.4', which is OK for EAP 6.1.1 but in order to work with EAP 6.2.0.ER6, this value has to be changed to 'urn:jboss:domain:1.5'.
If using installer with EAP 6.2.0.ER6, it throws no error, but continues as if everything was OK, which is confusing. I think it would be good to either redo the installer to work with EAP 6.2 as well or at least add some check that throws an error if the installation process is not done properly.