Hi, I just have a few questions to better serve you:
1) Which platform are you using, droid, mac, windows, or linux?
2) Have you previously used the client without issue?
Have you perhaps tried clearing your RSCR cache and then re-launching the client?
On windows, you may search for RSCRevolution to find the cache (folder).
Generally on Windows, it is located as seen below.
C:\Users\Mike\.rscrevolution
Mike = Your main PC user account
-Jax