6.2 RC1 is not qualified on RHEL 6.6 server. It is qualified only with RHEL 6.5 server.
However, between RHEL 6.5 and 6.6, there are not much differences and it should work. To diagnose this further, can you reply on the following questions:
1. Did you get any success message end of 6.2RC1 installation? Did you see username/password details ? Did you see URL details to login to UM server ?
2. What is the JRE version you are running on this box ? Can you share us the exact version that you have on your system ?
Regards,
Saravanan