This question is more specific to the Lotus Domino Java API, but the IOR is unable to be found on the Domino server. This could be the DIIOP task is not loaded on the Domino server or more likely you need to simply use the hostname rather than Domino server's hierarchical name. See
http://www.ibm.com/developerworks/lotus/library/ls-Java_access_pt1/index.html for reference.