Jin-Chong, thanks for the post. It worked!! Here are steps I took to resolve the issue.
1) Go to CMC / Servers / Service Categories / Explorer Services / Create new server / Service Category: Explorer services / Select Service: Explorer Exploration service
2) Repeat the above step for the next three servers
3) Restart the SIA and appache Tomcat
4) Test BO Explorer from the BO launch pad
Thanks for your help!!
Anthony